diff --git a/spec/compiler/codegen/private_spec.cr b/spec/compiler/codegen/private_spec.cr
index eee389178232..89fe3de809a5 100644
--- a/spec/compiler/codegen/private_spec.cr
+++ b/spec/compiler/codegen/private_spec.cr
@@ -1,5 +1,4 @@
 require "../../spec_helper"
-require "tempfile"
 
 describe "Codegen: private" do
   it "codegens private def in same file" do
@@ -15,13 +14,11 @@ describe "Codegen: private" do
     ]
     compiler.prelude = "empty"
 
-    tempfile = Tempfile.new("crystal-spec-output")
-    output_filename = tempfile.path
-    tempfile.close
+    output_filename = File.tempname("crystal-spec-output")
 
     compiler.compile sources, output_filename
   ensure
-    File.delete(tempfile.path) if tempfile
+    File.delete(output_filename) if output_filename
   end
 
   it "codegens overloaded private def in same file" do
@@ -42,13 +39,11 @@ describe "Codegen: private" do
     ]
     compiler.prelude = "empty"
 
-    tempfile = Tempfile.new("crystal-spec-output")
-    output_filename = tempfile.path
-    tempfile.close
+    output_filename = File.tempname("crystal-spec-output")
 
     compiler.compile sources, output_filename
   ensure
-    File.delete(tempfile.path) if tempfile
+    File.delete(output_filename) if output_filename
   end
 
   it "doesn't include filename for private types" do
diff --git a/spec/spec_helper.cr b/spec/spec_helper.cr
index 5ea235ae0cc6..75582e194aec 100644
--- a/spec/spec_helper.cr
+++ b/spec/spec_helper.cr
@@ -186,25 +186,23 @@ def run(code, filename = nil, inject_primitives = true, debug = Crystal::Debug::
 end
 
 def build_and_run(code)
-  code_file = Tempfile.new("build_and_run_code")
-  code_file.close
+  code_file = File.tempname("build_and_run_code")
 
   # write code to the temp file
-  File.write(code_file.path, code)
+  File.write(code_file, code)
 
-  binary_file = Tempfile.new("build_and_run_bin")
-  binary_file.close
+  binary_file = File.tempname("build_and_run_bin")
 
   `bin/crystal build #{code_file.path.inspect} -o #{binary_file.path.inspect}`
-  File.exists?(binary_file.path).should be_true
+  File.exists?(binary_file).should be_true
 
   out_io, err_io = IO::Memory.new, IO::Memory.new
-  status = Process.run(binary_file.path, output: out_io, error: err_io)
+  status = Process.run(binary_file, output: out_io, error: err_io)
 
   {status, out_io.to_s, err_io.to_s}
 ensure
-  File.delete(code_file.path) if code_file
-  File.delete(binary_file.path) if binary_file
+  File.delete(code_file) if code_file
+  File.delete(binary_file) if binary_file
 end
 
 def test_c(c_code, crystal_code)
diff --git a/spec/std/dir_spec.cr b/spec/std/dir_spec.cr
index 1b18f0ba883a..583f42a23cd1 100644
--- a/spec/std/dir_spec.cr
+++ b/spec/std/dir_spec.cr
@@ -342,6 +342,24 @@ describe "Dir" do
     end
   end
 
+  describe ".tempdir" do
+    it "returns default directory for tempfiles" do
+      old_tmpdir = ENV["TMPDIR"]?
+      ENV.delete("TMPDIR")
+      Dir.tempdir.should eq("/tmp")
+    ensure
+      ENV["TMPDIR"] = old_tmpdir
+    end
+
+    it "returns configure directory for tempfiles" do
+      old_tmpdir = ENV["TMPDIR"]?
+      ENV["TMPDIR"] = "/my/tmp"
+      Dir.tempdir.should eq("/my/tmp")
+    ensure
+      ENV["TMPDIR"] = old_tmpdir
+    end
+  end
+
   it "opens with new" do
     filenames = [] of String
 
diff --git a/spec/std/file/tempfile_spec.cr b/spec/std/file/tempfile_spec.cr
new file mode 100644
index 000000000000..26360c154a62
--- /dev/null
+++ b/spec/std/file/tempfile_spec.cr
@@ -0,0 +1,144 @@
+require "../spec_helper"
+
+describe File do
+  describe ".tempname" do
+    it "creates a path without creating the file" do
+      path = File.tempname
+
+      File.exists?(path).should be_false
+      File.dirname(path).should eq Dir.tempdir
+    end
+
+    it "accepts single suffix argument" do
+      path = File.tempname ".bar"
+
+      File.exists?(path).should be_false
+      File.dirname(path).should eq Dir.tempdir
+      File.extname(path).should eq(".bar")
+    end
+
+    it "accepts prefix and suffix arguments" do
+      path = File.tempname "foo", ".bar"
+
+      File.exists?(path).should be_false
+      File.dirname(path).should eq Dir.tempdir
+      File.extname(path).should eq(".bar")
+      File.basename(path).starts_with?("foo").should be_true
+    end
+
+    it "accepts prefix with separator" do
+      path = File.tempname "foo/", nil
+      File.dirname(path).should eq File.join(Dir.tempdir, "foo")
+      File.basename(path).starts_with?("foo").should be_false
+    end
+
+    it "accepts dir argument" do
+      path = File.tempname(dir: "foo")
+      File.dirname(path).should eq("foo")
+    end
+  end
+
+  describe ".tempfile" do
+    it "creates and writes" do
+      tempfile = File.tempfile
+      tempfile.print "Hello!"
+      tempfile.close
+
+      File.exists?(tempfile.path).should be_true
+      File.read(tempfile.path).should eq("Hello!")
+    ensure
+      tempfile.try &.delete
+    end
+
+    it "accepts single suffix argument" do
+      tempfile = File.tempfile ".bar"
+      tempfile.print "Hello!"
+      tempfile.close
+
+      File.extname(tempfile.path).should eq(".bar")
+
+      File.exists?(tempfile.path).should be_true
+      File.read(tempfile.path).should eq("Hello!")
+    ensure
+      tempfile.try &.delete
+    end
+
+    it "accepts prefix and suffix arguments" do
+      tempfile = File.tempfile "foo", ".bar"
+      tempfile.print "Hello!"
+      tempfile.close
+
+      File.extname(tempfile.path).should eq(".bar")
+      File.basename(tempfile.path).starts_with?("foo").should be_true
+
+      File.exists?(tempfile.path).should be_true
+      File.read(tempfile.path).should eq("Hello!")
+    ensure
+      tempfile.try &.delete
+    end
+
+    it "accepts dir argument" do
+      file = File.tempfile(dir: datapath)
+      File.dirname(file.path).should eq(datapath)
+    end
+
+    it "fails in unwritable folder" do
+      expect_raises(Errno, /mkstemp: ".*\/non-existing-folder\/.*": No such file or directory/) do
+        File.tempfile dir: datapath("non-existing-folder")
+      end
+    end
+
+    describe "with block" do
+      it "closes file" do
+        filepath = nil
+        tempfile = File.tempfile do |tempfile|
+          filepath = tempfile.path
+        end
+        tempfile.path.should eq filepath
+        tempfile.closed?.should be_true
+
+        filepath = filepath.not_nil!
+        File.exists?(filepath).should be_true
+      ensure
+        File.delete(filepath) if filepath
+      end
+
+      it "accepts single suffix argument" do
+        tempfile = File.tempfile(".bar") do |tempfile|
+          File.exists?(tempfile.path).should be_true
+          tempfile.closed?.should be_false
+        end
+        tempfile.closed?.should be_true
+
+        File.extname(tempfile.path).should eq(".bar")
+
+        File.exists?(tempfile.path).should be_true
+      ensure
+        File.delete(tempfile.path) if tempfile
+      end
+
+      it "accepts prefix and suffix arguments" do
+        tempfile = File.tempfile("foo", ".bar") do |tempfile|
+          File.exists?(tempfile.path).should be_true
+          tempfile.closed?.should be_false
+        end
+        tempfile.closed?.should be_true
+
+        File.extname(tempfile.path).should eq(".bar")
+        File.basename(tempfile.path).starts_with?("foo").should be_true
+
+        File.exists?(tempfile.path).should be_true
+      ensure
+        File.delete(tempfile.path) if tempfile
+      end
+
+      it "accepts dir argument" do
+        tempfile = File.tempfile(dir: datapath) do |tempfile|
+        end
+        File.dirname(tempfile.path).should eq(datapath)
+      ensure
+        File.delete(tempfile.path) if tempfile
+      end
+    end
+  end
+end
diff --git a/spec/std/file_spec.cr b/spec/std/file_spec.cr
index b97779cea242..c1f5e871ca90 100644
--- a/spec/std/file_spec.cr
+++ b/spec/std/file_spec.cr
@@ -1032,6 +1032,22 @@ describe "File" do
     end
   end
 
+  describe "#delete" do
+    it "deletes" do
+      path = datapath("file-to-be-deleted")
+      File.touch(path)
+
+      file = File.new path
+      file.close
+
+      File.exists?(path).should be_true
+      file.delete
+      File.exists?(path).should be_false
+    ensure
+      File.delete(path) if path && File.exists?(path)
+    end
+  end
+
   # TODO: these specs don't compile on win32 because iconv isn't implemented
   {% unless flag?(:win32) %}
     describe "encoding" do
diff --git a/spec/std/http/server/server_spec.cr b/spec/std/http/server/server_spec.cr
index 4dba0dff164a..baff008955bc 100644
--- a/spec/std/http/server/server_spec.cr
+++ b/spec/std/http/server/server_spec.cr
@@ -1,7 +1,6 @@
 require "spec"
 require "http/server"
 require "http/client/response"
-require "tempfile"
 require "../../../support/ssl"
 
 private class RaiseErrno < IO
@@ -354,8 +353,8 @@ module HTTP
     {% if flag?(:unix) %}
       describe "#bind_unix" do
         it "binds to different unix sockets" do
-          path1 = Tempfile.tempname
-          path2 = Tempfile.tempname
+          path1 = File.tempname
+          path2 = File.tempname
 
           begin
             server = Server.new do |context|
diff --git a/spec/std/tempfile_spec.cr b/spec/std/tempfile_spec.cr
deleted file mode 100644
index 7f01d835015a..000000000000
--- a/spec/std/tempfile_spec.cr
+++ /dev/null
@@ -1,105 +0,0 @@
-require "spec"
-require "tempfile"
-
-describe Tempfile do
-  describe "tempname" do
-    it "creates a path without creating the file" do
-      path = Tempfile.tempname
-
-      File.exists?(path).should be_false
-    end
-
-    it "has the given extension" do
-      path = Tempfile.tempname ".sock"
-
-      File.extname(path).should eq(".sock")
-    end
-  end
-
-  it "creates and writes" do
-    tempfile = Tempfile.new "foo"
-    tempfile.print "Hello!"
-    tempfile.close
-
-    File.exists?(tempfile.path).should be_true
-    File.read(tempfile.path).should eq("Hello!")
-  ensure
-    File.delete(tempfile.path) if tempfile
-  end
-
-  it "has given extension if passed to constructor" do
-    tempfile = Tempfile.new "foo", ".pdf"
-    File.extname(tempfile.path).should eq(".pdf")
-  end
-
-  it "creates and deletes" do
-    tempfile = Tempfile.new "foo"
-    tempfile.close
-    tempfile.delete
-
-    File.exists?(tempfile.path).should be_false
-  ensure
-    File.delete(tempfile.path) if tempfile && File.exists?(tempfile.path)
-  end
-
-  it "doesn't delete on open with block" do
-    tempfile = Tempfile.open("foo") do |f|
-      f.print "Hello!"
-    end
-    File.exists?(tempfile.path).should be_true
-  ensure
-    File.delete(tempfile.path) if tempfile
-  end
-
-  it "has given extension if passed to open" do
-    tempfile = Tempfile.open("foo", ".pdf") { |f| }
-    File.extname(tempfile.path).should eq(".pdf")
-  ensure
-    File.delete(tempfile.path) if tempfile
-  end
-
-  it "creates and writes with TMPDIR environment variable" do
-    old_tmpdir = ENV["TMPDIR"]?
-    ENV["TMPDIR"] = "/tmp"
-
-    tempfile = Tempfile.new "foo"
-    tempfile.print "Hello!"
-    tempfile.close
-
-    File.exists?(tempfile.path).should be_true
-    File.read(tempfile.path).should eq("Hello!")
-  ensure
-    ENV["TMPDIR"] = old_tmpdir if old_tmpdir
-    File.delete(tempfile.path) if tempfile
-  end
-
-  it "is seekable" do
-    tempfile = Tempfile.new "foo"
-    tempfile.puts "Hello!"
-    tempfile.seek(0, IO::Seek::Set)
-    tempfile.tell.should eq(0)
-    tempfile.pos.should eq(0)
-    tempfile.gets(chomp: false).should eq("Hello!\n")
-    tempfile.pos = 0
-    tempfile.gets(chomp: false).should eq("Hello!\n")
-    tempfile.close
-  ensure
-    File.delete(tempfile.path) if tempfile
-  end
-
-  it "returns default directory for tempfiles" do
-    old_tmpdir = ENV["TMPDIR"]?
-    ENV.delete("TMPDIR")
-    Tempfile.dirname.should eq("/tmp")
-  ensure
-    ENV["TMPDIR"] = old_tmpdir if old_tmpdir
-  end
-
-  it "returns configure directory for tempfiles" do
-    old_tmpdir = ENV["TMPDIR"]?
-    ENV["TMPDIR"] = "/my/tmp"
-    Tempfile.dirname.should eq("/my/tmp")
-  ensure
-    ENV["TMPDIR"] = old_tmpdir if old_tmpdir
-  end
-end
diff --git a/spec/support/tempfile.cr b/spec/support/tempfile.cr
index bc465dd85dff..4dd15f511c79 100644
--- a/spec/support/tempfile.cr
+++ b/spec/support/tempfile.cr
@@ -1,10 +1,9 @@
-require "tempfile"
 require "file_utils"
 
 {% if flag?(:win32) %}
-  SPEC_TEMPFILE_PATH = File.join(Tempfile.dirname, "cr-spec-#{Random.new.hex(4)}").gsub("C:\\", '/').gsub('\\', '/')
+  SPEC_TEMPFILE_PATH = File.join(Dir.tempdir, "cr-spec-#{Random.new.hex(4)}").gsub("C:\\", '/').gsub('\\', '/')
 {% else %}
-  SPEC_TEMPFILE_PATH = File.join(Tempfile.dirname, "cr-spec-#{Random.new.hex(4)}")
+  SPEC_TEMPFILE_PATH = File.join(Dir.tempdir, "cr-spec-#{Random.new.hex(4)}")
 {% end %}
 
 SPEC_TEMPFILE_CLEANUP = ENV["SPEC_TEMPFILE_CLEANUP"]? != "0"
@@ -17,7 +16,7 @@ SPEC_TEMPFILE_CLEANUP = ENV["SPEC_TEMPFILE_CLEANUP"]? != "0"
 # The constructed path is yielded to the block and cleaned up afterwards.
 #
 # Paths should still be uniquely chosen inside a spec file. This helper
-# ensures they're placed in the temporary location (`Tempfile.dirname`),
+# ensures they're placed in the temporary location (`Dir.tempdir`),
 # avoids name clashes between parallel spec runs and cleans up afterwards.
 #
 # The unique directory for the spec run is removed `at_exit`.
diff --git a/src/compiler/crystal/tools/playground/server.cr b/src/compiler/crystal/tools/playground/server.cr
index 946daa6dfcbe..460c1ec19ed5 100644
--- a/src/compiler/crystal/tools/playground/server.cr
+++ b/src/compiler/crystal/tools/playground/server.cr
@@ -1,5 +1,4 @@
 require "http/server"
-require "tempfile"
 require "logger"
 require "ecr/macros"
 require "markdown"
diff --git a/src/crystal/system/unix/dir.cr b/src/crystal/system/unix/dir.cr
index 1a3fe5b41b67..8dc5e950f844 100644
--- a/src/crystal/system/unix/dir.cr
+++ b/src/crystal/system/unix/dir.cr
@@ -48,6 +48,11 @@ module Crystal::System::Dir
     path
   end
 
+  def self.tempdir
+    tmpdir = ENV["TMPDIR"]? || "/tmp"
+    tmpdir.rchop(::File::SEPARATOR)
+  end
+
   def self.create(path : String, mode : Int32) : Nil
     if LibC.mkdir(path.check_no_null_byte, mode) == -1
       raise Errno.new("Unable to create directory '#{path}'")
diff --git a/src/crystal/system/unix/file.cr b/src/crystal/system/unix/file.cr
index b927d2bb9b0c..4599d1bdad0e 100644
--- a/src/crystal/system/unix/file.cr
+++ b/src/crystal/system/unix/file.cr
@@ -12,25 +12,20 @@ module Crystal::System::File
     fd
   end
 
-  def self.mktemp(name, extension)
-    tmpdir = tempdir + ::File::SEPARATOR
-    path = "#{tmpdir}#{name}.XXXXXX#{extension}"
+  def self.mktemp(prefix, suffix, dir) : {LibC::Int, String}
+    dir = dir + ::File::SEPARATOR
+    path = "#{dir}#{prefix}.XXXXXX#{suffix}"
 
-    if extension
-      fd = LibC.mkstemps(path, extension.bytesize)
+    if suffix
+      fd = LibC.mkstemps(path, suffix.bytesize)
     else
       fd = LibC.mkstemp(path)
     end
 
-    raise Errno.new("mkstemp") if fd == -1
+    raise Errno.new("mkstemp: #{path.inspect}") if fd == -1
     {fd, path}
   end
 
-  def self.tempdir
-    tmpdir = ENV["TMPDIR"]? || "/tmp"
-    tmpdir.rchop(::File::SEPARATOR)
-  end
-
   def self.info?(path : String, follow_symlinks : Bool) : ::File::Info?
     stat = uninitialized LibC::Stat
     if follow_symlinks
diff --git a/src/crystal/system/win32/dir.cr b/src/crystal/system/win32/dir.cr
index 87171e21b941..2c9fe3dec367 100644
--- a/src/crystal/system/win32/dir.cr
+++ b/src/crystal/system/win32/dir.cr
@@ -84,6 +84,21 @@ module Crystal::System::Dir
     path
   end
 
+  def self.tempdir : String
+    tmpdir = System.retry_wstr_buffer do |buffer, small_buf|
+      len = LibC.GetTempPathW(buffer.size, buffer)
+      if 0 < len < buffer.size
+        break String.from_utf16(buffer[0, len])
+      elsif small_buf && len > 0
+        next len
+      else
+        raise WinError.new("Error while getting current directory")
+      end
+    end
+
+    tmpdir.rchop("\\")
+  end
+
   def self.create(path : String, mode : Int32) : Nil
     if LibC._wmkdir(to_windows_path(path)) == -1
       raise Errno.new("Unable to create directory '#{path}'")
diff --git a/src/crystal/system/win32/file.cr b/src/crystal/system/win32/file.cr
index 664d15a71575..3618e4fe5bcb 100644
--- a/src/crystal/system/win32/file.cr
+++ b/src/crystal/system/win32/file.cr
@@ -25,8 +25,8 @@ module Crystal::System::File
     fd
   end
 
-  def self.mktemp(name : String, extension : String?) : {LibC::Int, String}
-    path = "#{tempdir}\\#{name}.#{::Random::Secure.hex}#{extension}"
+  def self.mktemp(prefix : String, suffix : String?, dir : String) : {LibC::Int, String}
+    path = "#{tempdir}\\#{prefix}.#{::Random::Secure.hex}#{suffix}"
 
     fd = LibC._wopen(to_windows_path(path), LibC::O_RDWR | LibC::O_CREAT | LibC::O_EXCL | LibC::O_BINARY, ::File::DEFAULT_CREATE_PERMISSIONS)
     if fd == -1
@@ -36,21 +36,6 @@ module Crystal::System::File
     {fd, path}
   end
 
-  def self.tempdir : String
-    tmpdir = System.retry_wstr_buffer do |buffer, small_buf|
-      len = LibC.GetTempPathW(buffer.size, buffer)
-      if 0 < len < buffer.size
-        break String.from_utf16(buffer[0, len])
-      elsif small_buf && len > 0
-        next len
-      else
-        raise WinError.new("Error while getting current directory")
-      end
-    end
-
-    tmpdir.rchop("\\")
-  end
-
   NOT_FOUND_ERRORS = {
     WinError::ERROR_FILE_NOT_FOUND,
     WinError::ERROR_PATH_NOT_FOUND,
diff --git a/src/dir.cr b/src/dir.cr
index 79f283720f4f..239f20c603a8 100644
--- a/src/dir.cr
+++ b/src/dir.cr
@@ -159,6 +159,15 @@ class Dir
     end
   end
 
+  # Returns the tmp dir used for tempfile.
+  #
+  # ```
+  # Dir.tempdir # => "/tmp"
+  # ```
+  def self.tempdir : String
+    Crystal::System::Dir.tempdir
+  end
+
   # See `#each`.
   def self.each(dirname)
     Dir.open(dirname) do |dir|
diff --git a/src/docs_main.cr b/src/docs_main.cr
index f36e9cbf8d1a..c44c68fcdee1 100644
--- a/src/docs_main.cr
+++ b/src/docs_main.cr
@@ -54,7 +54,6 @@ require "./readline"
 require "./signal"
 require "./string_pool"
 require "./string_scanner"
-require "./tempfile"
 require "./uri"
 require "./uuid"
 require "./uuid/json"
diff --git a/src/file.cr b/src/file.cr
index 9a904f4d7735..696e2bd6b505 100644
--- a/src/file.cr
+++ b/src/file.cr
@@ -1,5 +1,48 @@
 require "crystal/system/file"
 
+# A `File` instance represents a file entry in the local file system and allows using it as an `IO`.
+#
+# ```
+# file = File.new("path/to/file")
+# content = file.gets_to_end
+# file.close
+#
+# # Implicit close with `open`
+# content = File.open("path/to/file") do |file|
+#   file.gets_to_end
+# end
+#
+# # Shortcut:
+# content = File.read("path/to/file")
+# ```
+#
+# ## Temporary Files
+#
+# Every tempfile is operated as a `File`, including initializing, reading and writing.
+#
+# ```
+# tempfile = File.tempfile("foo")
+#
+# File.size(tempfile.path)                   # => 6
+# File.info(tempfile.path).modification_time # => 2015-10-20 13:11:12 UTC
+# File.exists?(tempfile.path)                # => true
+# File.read_lines(tempfile.path)             # => ["foobar"]
+# ```
+#
+# Files created from `tempfile` are stored in a directory that handles
+# temporary files (`Dir.tempdir`):
+#
+# ```
+# File.tempfile("foo").path # => "/tmp/foo.ulBCPS"
+# ```
+#
+# It is encouraged to delete a tempfile after using it, which
+# ensures they are not left behind in your filesystem until garbage collected.
+#
+# ```
+# tempfile = File.tempfile("foo")
+# tempfile.delete
+# ```
 class File < IO::FileDescriptor
   # The file/directory separator character. `'/'` on all platforms.
   SEPARATOR = '/'
@@ -860,6 +903,11 @@ class File < IO::FileDescriptor
   def flock_unlock
     system_flock_unlock
   end
+
+  # Deletes this file.
+  def delete
+    File.delete(@path)
+  end
 end
 
 require "./file/*"
diff --git a/src/file/tempfile.cr b/src/file/tempfile.cr
new file mode 100644
index 000000000000..7ba9e6b66d48
--- /dev/null
+++ b/src/file/tempfile.cr
@@ -0,0 +1,138 @@
+class File
+  # Returns a fully-qualified path to a temporary file.
+  # The file is not actually created on the file system.
+  #
+  # ```
+  # File.tempname("foo", ".sock") # => "/tmp/foo20171206-1234-449386.sock"
+  # ```
+  #
+  # *prefix* and *suffix* are appended to the front and end of the file name, respectively.
+  # These values may contain directory separators.
+  #
+  # The path will be placed in *dir* which defaults to the standard temporary directory `Dir.tempdir`.
+  def self.tempname(prefix : String?, suffix : String?, *, dir : String = Dir.tempdir)
+    name = String.build do |io|
+      if prefix
+        io << prefix
+        io << '-'
+      end
+
+      io << Time.now.to_s("%Y%m%d")
+      io << '-'
+
+      {% unless flag?(:win32) %}
+        # TODO: Remove this once Process is implemented
+        io << Process.pid
+        io << '-'
+      {% end %}
+
+      io << Random.rand(0x100000000).to_s(36)
+
+      io << suffix
+    end
+
+    File.join(dir, name)
+  end
+
+  # Returns a fully-qualified path to a temporary file.
+  # The optional *suffix* is appended to the file name.
+  #
+  # ```
+  # File.tempname          # => "/tmp/20171206-1234-449386"
+  # File.tempname(".sock") # => "/tmp/20171206-1234-449386.sock"
+  # ```
+  def self.tempname(suffix : String? = nil, *, dir : String = Dir.tempdir)
+    tempname(prefix: nil, suffix: suffix, dir: dir)
+  end
+
+  # Creates a temporary file.
+  #
+  # ```
+  # tempfile = File.tempfile("foo", ".bar")
+  # tempfile.delete
+  # ```
+  #
+  # *prefix* and *suffix* are appended to the front and end of the file name, respectively.
+  # These values may contain directory separators.
+  #
+  # The file will be placed in *dir* which defaults to the standard temporary directory `Dir.tempdir`.
+  #
+  # *encoding* and *invalid* are passed to `IO#set_encoding`.
+  #
+  # It is the caller's responsibility to remove the file when no longer needed.
+  def self.tempfile(prefix : String?, suffix : String?, *, dir : String = Dir.tempdir, encoding = nil, invalid = nil)
+    fileno, path = Crystal::System::File.mktemp(prefix, suffix, dir)
+    new(path, fileno, blocking: true, encoding: encoding, invalid: invalid)
+  end
+
+  # Creates a temporary file.
+  #
+  # ```
+  # tempfile = File.tempfile(".bar")
+  # tempfile.delete
+  # ```
+  #
+  # *prefix* and *suffix* are appended to the front and end of the file name, respectively.
+  # These values may contain directory separators.
+  #
+  # The file will be placed in *dir* which defaults to the standard temporary directory `Dir.tempdir`.
+  #
+  # *encoding* and *invalid* are passed to `IO#set_encoding`.
+  #
+  # It is the caller's responsibility to remove the file when no longer needed.
+  def self.tempfile(suffix : String? = nil, *, dir : String = Dir.tempdir, encoding = nil, invalid = nil)
+    tempfile(prefix: nil, suffix: suffix, dir: dir, encoding: encoding, invalid: invalid)
+  end
+
+  # Creates a temporary file and yields it to the given block. It is closed and returned at the end of this method call.
+  #
+  # ```
+  # tempfile = File.tempfile("foo", ".bar") do |file|
+  #   file.print("bar")
+  # end
+  # File.read(tempfile.path) # => "bar"
+  # tempfile.delete
+  # ```
+  #
+  # *prefix* and *suffix* are appended to the front and end of the file name, respectively.
+  # These values may contain directory separators.
+  #
+  # The file will be placed in *dir* which defaults to the standard temporary directory `Dir.tempdir`.
+  #
+  # *encoding* and *invalid* are passed to `IO#set_encoding`.
+  #
+  # It is the caller's responsibility to remove the file when no longer needed.
+  def self.tempfile(prefix : String?, suffix : String?, *, dir : String = Dir.tempdir, encoding = nil, invalid = nil)
+    tempfile = tempfile(prefix: prefix, suffix: suffix, dir: dir, encoding: encoding, invalid: invalid)
+    begin
+      yield tempfile
+    ensure
+      tempfile.close
+    end
+    tempfile
+  end
+
+  # Creates a temporary file and yields it to the given block. It is closed and returned at the end of this method call.
+  #
+  # ```
+  # tempfile = File.tempfile(".bar") do |file|
+  #   file.print("bar")
+  # end
+  # File.read(tempfile.path) # => "bar"
+  # tempfile.delete
+  # ```
+  #
+  # *prefix* and *suffix* are appended to the front and end of the file name, respectively.
+  # These values may contain directory separators.
+  #
+  # The file will be placed in *dir* which defaults to the standard temporary directory `Dir.tempdir`.
+  #
+  # *encoding* and *invalid* are passed to `IO#set_encoding`.
+  #
+  # It is the caller's responsibility to remove the file when no longer needed.
+  def self.tempfile(suffix : String? = nil, *, dir : String = Dir.tempdir, encoding = nil, invalid = nil)
+    tempfile(prefix: nil, suffix: suffix, dir: dir, encoding: encoding, invalid: invalid) do |tempfile|
+      yield tempfile
+    end
+  end
+end
diff --git a/src/http/formdata.cr b/src/http/formdata.cr
index fafdc35315a9..f7d63526f836 100644
--- a/src/http/formdata.cr
+++ b/src/http/formdata.cr
@@ -20,7 +20,7 @@ require "./formdata/**"
 #     when "name"
 #       name = part.body.gets_to_end
 #     when "file"
-#       file = Tempfile.open("upload") do |file|
+#       file = File.tempfile("upload") do |file|
 #         IO.copy(part.body, file)
 #       end
 #     end
diff --git a/src/tempfile.cr b/src/tempfile.cr
deleted file mode 100644
index cd2926db6b43..000000000000
--- a/src/tempfile.cr
+++ /dev/null
@@ -1,113 +0,0 @@
-require "c/stdlib"
-
-# The `Tempfile` class is for managing temporary files.
-# Every tempfile is operated as a `File`, including
-# initializing, reading and writing.
-#
-# ```
-# tempfile = Tempfile.new("foo")
-# # or
-# tempfile = Tempfile.open("foo") do |file|
-#   file.print("foobar")
-# end
-#
-# File.size(tempfile.path)                   # => 6
-# File.info(tempfile.path).modification_time # => 2015-10-20 13:11:12 UTC
-# File.exists?(tempfile.path)                # => true
-# File.read_lines(tempfile.path)             # => ["foobar"]
-# ```
-#
-# Files created from this class are stored in a directory that handles
-# temporary files.
-#
-# ```
-# Tempfile.new("foo").path # => "/tmp/foo.ulBCPS"
-# ```
-#
-# Also, it is encouraged to delete a tempfile after using it, which
-# ensures they are not left behind in your filesystem until garbage collected.
-#
-# ```
-# tempfile = Tempfile.new("foo")
-# tempfile.delete
-# ```
-#
-# The optional `extension` argument can be used to force the resulting filename
-# to end with the given extension.
-#
-# ```
-# Tempfile.new("foo", ".png").path # => "/tmp/foo.ulBCPS.png"
-# ```
-class Tempfile < File
-  # Creates a `Tempfile` with the given filename and extension.
-  #
-  # *encoding* and *invalid* are passed to `IO#set_encoding`.
-  def initialize(name, extension = nil, encoding = nil, invalid = nil)
-    fileno, path = Crystal::System::File.mktemp(name, extension)
-    super(path, fileno, blocking: true, encoding: encoding, invalid: invalid)
-  end
-
-  # Retrieves the full path of a this tempfile.
-  #
-  # ```
-  # Tempfile.new("foo").path # => "/tmp/foo.ulBCPS"
-  # ```
-  getter path : String
-
-  # Returns a fully-qualified path to a temporary file without actually
-  # creating the file.
-  #
-  # ```
-  # Tempfile.tempname # => "/tmp/20171206-1234-449386"
-  # ```
-  #
-  # The optional `extension` argument can be used to make the resulting
-  # filename to end with the given extension.
-  #
-  # ```
-  # Tempfile.tempname(".sock") # => "/tmp/20171206-1234-449386.sock"
-  # ```
-  def self.tempname(extension = nil)
-    time = Time.now.to_s("%Y%m%d")
-    rand = Random.rand(0x100000000).to_s(36)
-    {% if flag?(:win32) %}
-      # TODO: Remove this once Process is implemented
-      File.join(dirname, "#{time}-#{rand}#{extension}")
-    {% else %}
-      File.join(dirname, "#{time}-#{Process.pid}-#{rand}#{extension}")
-    {% end %}
-  end
-
-  # Creates a file with *filename* and *extension*, and yields it to the given
-  # block. It is closed and returned at the end of this method call.
-  #
-  # ```
-  # tempfile = Tempfile.open("foo") do |file|
-  #   file.print("bar")
-  # end
-  # File.read(tempfile.path) # => "bar"
-  # ```
-  def self.open(filename, extension = nil)
-    tempfile = Tempfile.new(filename, extension)
-    begin
-      yield tempfile
-    ensure
-      tempfile.close
-    end
-    tempfile
-  end
-
-  # Returns the tmp dir used for tempfile.
-  #
-  # ```
-  # Tempfile.dirname # => "/tmp"
-  # ```
-  def self.dirname : String
-    Crystal::System::File.tempdir
-  end
-
-  # Deletes this tempfile.
-  def delete
-    File.delete(@path)
-  end
-end