diff --git a/src/Codor/Sniffs/Files/FunctionLengthSniff.php b/src/Codor/Sniffs/Files/FunctionLengthSniff.php
new file mode 100644
index 0000000..1e56028
--- /dev/null
+++ b/src/Codor/Sniffs/Files/FunctionLengthSniff.php
@@ -0,0 +1,38 @@
+<?php
+
+namespace Codor\Sniffs\Files;
+
+use PHP_CodeSniffer_Sniff;
+use PHP_CodeSniffer_File;
+
+class FunctionLengthSniff implements PHP_CodeSniffer_Sniff
+{
+
+    protected $maxLength = 20;
+
+    public function register()
+    {
+        return [T_FUNCTION];
+    }
+
+    public function process(PHP_CodeSniffer_File $phpcsFile, $stackPtr)
+    {
+        $tokens = $phpcsFile->getTokens();
+        $token = $tokens[$stackPtr];
+
+        // Skip function without body.
+        if (isset($token['scope_opener']) === false) {
+            return 0;
+        }
+
+        $firstToken = $tokens[$token['scope_opener']];
+        $lastToken = $tokens[$token['scope_closer']];
+        $length = $lastToken['line'] - $firstToken['line'];
+
+        if ($length > $this->maxLength) {
+            $tokenType = strtolower(substr($token['type'], 2));
+            $error = "Function is {$length} lines. Must be {$this->maxLength} lines or fewer.";
+            $phpcsFile->addError($error, $stackPtr, sprintf('%sTooBig', ucfirst($tokenType)));
+        }
+    }
+}
diff --git a/tests/Sniffs/Files/Assets/FunctionLengthSniff/FunctionLengthSniff.inc b/tests/Sniffs/Files/Assets/FunctionLengthSniff/FunctionLengthSniff.inc
new file mode 100644
index 0000000..3fd20db
--- /dev/null
+++ b/tests/Sniffs/Files/Assets/FunctionLengthSniff/FunctionLengthSniff.inc
@@ -0,0 +1,62 @@
+<?php
+
+function someFunctionLongerThan21Lines()
+{
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+}
+
+function someFunctionLessThan21Lines()
+{
+
+}
+
+class SomeClass
+{
+    public function someMethodLongerThan21Lines()
+    {
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+    }
+
+    public function someMethodLessThan21Lines()
+    {
+    
+    }
+}
\ No newline at end of file
diff --git a/tests/Sniffs/Files/FunctionLengthSniffTest.php b/tests/Sniffs/Files/FunctionLengthSniffTest.php
new file mode 100644
index 0000000..c304439
--- /dev/null
+++ b/tests/Sniffs/Files/FunctionLengthSniffTest.php
@@ -0,0 +1,22 @@
+<?php
+
+namespace Codor\Tests\Sniffs\ControlStructures;
+
+use Codor\Tests\CodeSnifferRunner;
+use PHPUnit\Framework\TestCase;
+
+/** @group Files */
+class FunctionLengthSniffTest extends TestCase
+{
+	/** @test */
+    public function it_detects_functions_that_are_over_the_max_allowed()
+    {
+        $codeSnifferRunner = new CodeSnifferRunner();
+        $errorCount = $codeSnifferRunner->detectErrorCountInFileForSniff(
+            __DIR__.'/Assets/FunctionLengthSniff/FunctionLengthSniff.inc',
+            'Codor.Files.FunctionLength'
+        );
+
+        $this->assertSame(2, $errorCount);
+    }
+}
\ No newline at end of file