diff --git a/ports/libopensp/opensp_1.5.2-13.diff b/ports/libopensp/opensp_1.5.2-13.diff
new file mode 100644
index 00000000000000..92781232fd4861
--- /dev/null
+++ b/ports/libopensp/opensp_1.5.2-13.diff
@@ -0,0 +1,37 @@
+--- opensp-1.5.2.orig/sx/XmlOutputEventHandler.cxx
++++ opensp-1.5.2/sx/XmlOutputEventHandler.cxx
+@@ -1199,12 +1199,22 @@
+           // Check to make sure we haven't passed outside of the
+           // output directory
+ 	  char *dirs = strdup (filePath);
++#ifdef MAXPATHLEN
+           char realDirs[MAXPATHLEN];
+           char realOutputDir[MAXPATHLEN];
++#else
++          char *realDirs;
++          char *realOutputDir;
++#endif
+           char *outputDir = strdup(outputDir_);
+ 
++#ifdef MAXPATHLEN
+           realpath((const char *)dirname(dirs), realDirs);
+           realpath((const char *)dirname(outputDir), realOutputDir);
++#else
++          realDirs = realpath((const char *)dirname(dirs), NULL);
++          realOutputDir = realpath((const char *)dirname(outputDir), NULL);
++#endif
+ 
+           if (strncmp(realDirs, realOutputDir, strlen (realOutputDir)) != 0) {
+             app_->message(XmlOutputMessages::pathOutsideOutputDirectory,
+@@ -1214,6 +1224,11 @@
+             }
+           }
+ 
++#ifndef MAXPATHLEN
++	  free(realDirs);
++	  free(realOutputDir);
++#endif
++
+ 	  // Make the necessary directories
+ 	  maybeCreateDirectories(dirname(dirs));
+ 
diff --git a/ports/libopensp/portfile.cmake b/ports/libopensp/portfile.cmake
new file mode 100644
index 00000000000000..aa7fdadfffb46d
--- /dev/null
+++ b/ports/libopensp/portfile.cmake
@@ -0,0 +1,56 @@
+set(OPENSP_VERSION 1.5.2)
+
+set(PATCHES opensp_1.5.2-13.diff)                   # http://deb.debian.org/debian/pool/main/o/opensp/opensp_1.5.2-13.diff.gz
+if (VCPKG_TARGET_IS_WINDOWS OR VCPKG_TARGET_IS_UWP)
+    list(APPEND PATCHES windows_cmake_build.diff)   # https://invent.kde.org/packaging/craft-blueprints-kde/-/tree/master/libs/libopensp
+endif()
+if (VCPKG_TARGET_IS_UWP)
+    list(APPEND PATCHES uwp_getenv_fix.diff)
+endif()
+
+vcpkg_download_distfile(ARCHIVE
+    URLS "https://downloads.sourceforge.net/project/openjade/opensp/${OPENSP_VERSION}/OpenSP-${OPENSP_VERSION}.tar.gz"
+    FILENAME "OpenSP-${OPENSP_VERSION}.tar.gz"
+    SHA512 a7dcc246ba7f58969ecd6d107c7b82dede811e65f375b7aa3e683621f2c6ff3e7dccefdd79098fcadad6cca8bb94c2933c63f4701be2c002f9a56f1bbe6b047e
+)
+
+vcpkg_extract_source_archive_ex(
+    OUT_SOURCE_PATH SOURCE_PATH
+    ARCHIVE "${ARCHIVE}"
+    REF ${OPENSP_VERSION}
+    PATCHES ${PATCHES}
+)
+
+if (VCPKG_TARGET_IS_WINDOWS OR VCPKG_TARGET_IS_UWP)
+    vcpkg_cmake_configure(
+        SOURCE_PATH "${SOURCE_PATH}"
+    )
+
+    vcpkg_cmake_install()
+else()
+    set(EXTRA_OPTS "")
+    if(VCPKG_TARGET_IS_OSX)
+        list(APPEND EXTRA_OPTS "LDFLAGS=-framework CoreFoundation \$LDFLAGS") # libintl links to it
+    endif()
+
+    vcpkg_configure_make(
+        AUTOCONFIG
+        SOURCE_PATH "${SOURCE_PATH}"
+        OPTIONS
+            --disable-doc-build
+            ${EXTRA_OPTS}
+    )
+
+    vcpkg_install_make()
+endif()
+
+vcpkg_fixup_pkgconfig()
+vcpkg_copy_pdbs()
+
+if(VCPKG_LIBRARY_LINKAGE STREQUAL "static")
+    file(REMOVE_RECURSE "${CURRENT_PACKAGES_DIR}/bin" "${CURRENT_PACKAGES_DIR}/debug/bin")
+endif()
+
+file(REMOVE_RECURSE "${CURRENT_PACKAGES_DIR}/debug/share")
+file(REMOVE_RECURSE "${CURRENT_PACKAGES_DIR}/debug/include")
+file(INSTALL "${SOURCE_PATH}/COPYING" DESTINATION "${CURRENT_PACKAGES_DIR}/share/${PORT}" RENAME copyright)
diff --git a/ports/libopensp/uwp_getenv_fix.diff b/ports/libopensp/uwp_getenv_fix.diff
new file mode 100644
index 00000000000000..806ac1ba86e76e
--- /dev/null
+++ b/ports/libopensp/uwp_getenv_fix.diff
@@ -0,0 +1,13 @@
+diff --git a/config.h b/config.h
+index 6a2b097..7db8a93 100644
+--- a/config.h
++++ b/config.h
+@@ -64,6 +64,8 @@
+ #pragma warning ( disable : 4251 ) // __declspec(dllexport)
+ #pragma warning ( disable : 4275 )
+ #pragma warning ( disable : 4237 ) // future reserved keyword
++#pragma warning ( disable : 4996 ) // 'getenv': This function or variable may be unsafe (on UWP)
++#pragma warning ( disable : 4703 ) // potentially uninitialized local pointer variable 'declaredValue'
+ #define huge verybig
+ #if _MSC_VER == 900
+ #define SP_DECLARE_PLACEMENT_OPERATOR_NEW
diff --git a/ports/libopensp/vcpkg.json b/ports/libopensp/vcpkg.json
new file mode 100644
index 00000000000000..b61ba7152520df
--- /dev/null
+++ b/ports/libopensp/vcpkg.json
@@ -0,0 +1,22 @@
+{
+  "name": "libopensp",
+  "version": "1.5.2",
+  "description": "SGML parser algorithm",
+  "homepage": "http://openjade.sourceforge.net",
+  "dependencies": [
+    {
+      "name": "gettext",
+      "platform": "!(windows | uwp)"
+    },
+    {
+      "name": "vcpkg-cmake",
+      "host": true,
+      "platform": "windows"
+    },
+    {
+      "name": "vcpkg-cmake-config",
+      "host": true,
+      "platform": "windows"
+    }
+  ]
+}
diff --git a/ports/libopensp/windows_cmake_build.diff b/ports/libopensp/windows_cmake_build.diff
new file mode 100644
index 00000000000000..2c9e8253732993
--- /dev/null
+++ b/ports/libopensp/windows_cmake_build.diff
@@ -0,0 +1,142 @@
+diff -Nru -x '*~' OpenSP-1.5.2.orig/CMakeLists.txt OpenSP-1.5.2/CMakeLists.txt
+--- OpenSP-1.5.2.orig/CMakeLists.txt	1970-01-01 02:00:00.000000000 +0200
++++ OpenSP-1.5.2/CMakeLists.txt	2014-08-24 17:23:19.941495700 +0300
+@@ -0,0 +1,24 @@
++project(opensp)
++
++set (VERSION_MAJOR 1)
++set (VERSION_MINOR 5)
++set (VERSION_PATH 2)
++
++cmake_minimum_required(VERSION 2.6)
++
++include_directories(
++    .
++    include
++    generic
++)
++
++file(GLOB SRC_SOURCES lib/*.cxx)
++file(GLOB libopensp_HEADERS config.h generic/*.h include/*.h)
++
++add_library(opensp ${SRC_SOURCES})
++set_target_properties(opensp PROPERTIES OUTPUT_NAME "osp")
++target_link_libraries(opensp)
++
++install(TARGETS opensp RUNTIME DESTINATION bin ARCHIVE DESTINATION lib LIBRARY DESTINATION lib)
++install(FILES ${libopensp_HEADERS} DESTINATION include/opensp)
++
+diff -Nru -x '*~' OpenSP-1.5.2.orig/config.h OpenSP-1.5.2/config.h
+--- OpenSP-1.5.2.orig/config.h	2005-12-23 16:16:30.000000000 +0200
++++ OpenSP-1.5.2/config.h	2014-08-24 17:26:33.724698900 +0300
+@@ -26,6 +26,12 @@
+ #endif
+ #endif /* __GNUG__ */
+ 
++#ifdef __MINGW32__
++#define SP_HAVE_BOOL
++#define SP_HAVE_TYPENAME
++#define SP_DEFINE_TEMPLATES
++#endif /* __MINGW32__ */
++
+ #if defined(sun) || defined(__sun)
+ // struct stat has st_blksize member
+ #define SP_STAT_BLKSIZE
+@@ -80,6 +86,11 @@
+ #define SP_HAVE_TYPENAME
+ #endif
+ 
++#if _MSC_VER >=1800
++// Visual Studio 2013
++#define SP_ANSI_FOR_SCOPE
++#endif
++
+ #define SP_HAVE_SETMODE
+ #define SP_DLLEXPORT __declspec(dllexport)
+ #define SP_DLLIMPORT __declspec(dllimport)
+@@ -301,15 +312,8 @@
+ #define PATH_SEPARATOR ':'
+ #endif
+ 
+-
+-/* new stuff */
+-
+-#ifndef HAVE_MUTABLE
+-#define mutable
+-#endif
+-
+ // NOTE: This is processed as a Makefile, not as a header by autoconf.
+-#define SP_PACKAGE "OpenSP"
+-#define SP_VERSION "1.5.2"
++#define SP_PACKAGE "@PACKAGE@"
++#define SP_VERSION "@VERSION@"
+ 
+ #endif /* not config_INCLUDED */
+diff -Nru -x '*~' OpenSP-1.5.2.orig/generic/SGMLApplication.h OpenSP-1.5.2/generic/SGMLApplication.h
+--- OpenSP-1.5.2.orig/generic/SGMLApplication.h	2005-05-14 12:17:41.000000000 +0300
++++ OpenSP-1.5.2/generic/SGMLApplication.h	2014-08-24 17:23:19.957120700 +0300
+@@ -269,6 +269,7 @@
+     unsigned count_;
+     friend class OpenEntityPtr;
+   };
++  SGMLApplication();
+   virtual ~SGMLApplication();
+   virtual void appinfo(const AppinfoEvent &);
+   virtual void startDtd(const StartDtdEvent &);
+diff -Nru -x '*~' OpenSP-1.5.2.orig/include/OutputCharStream.h OpenSP-1.5.2/include/OutputCharStream.h
+--- OpenSP-1.5.2.orig/include/OutputCharStream.h	2005-07-21 17:04:39.000000000 +0300
++++ OpenSP-1.5.2/include/OutputCharStream.h	2014-08-24 17:23:19.957120700 +0300
+@@ -31,6 +31,7 @@
+   OutputCharStream &operator<<(const char *);
+   OutputCharStream &operator<<(const StringC &);
+   OutputCharStream &operator<<(unsigned long);
++  OutputCharStream &operator<<(unsigned long long);
+   OutputCharStream &operator<<(int);
+   OutputCharStream &operator<<(Newline);
+ private:
+diff -Nru -x '*~' OpenSP-1.5.2.orig/lib/MessageReporter.cxx OpenSP-1.5.2/lib/MessageReporter.cxx
+--- OpenSP-1.5.2.orig/lib/MessageReporter.cxx	2005-07-21 17:05:17.000000000 +0300
++++ OpenSP-1.5.2/lib/MessageReporter.cxx	2014-08-24 17:23:19.957120700 +0300
+@@ -123,7 +123,11 @@
+     os() << ':';
+   }
+   if (options_ & messageNumbers)
++#ifdef _WIN64
++    os() << (unsigned long long)message.type->module() << "." 
++#else
+     os() << (unsigned long)message.type->module() << "." 
++#endif
+       << (unsigned long)message.type->number() << ":";
+   switch (message.type->severity()) {
+   case MessageType::info:
+diff -Nru -x '*~' OpenSP-1.5.2.orig/lib/OutputCharStream.cxx OpenSP-1.5.2/lib/OutputCharStream.cxx
+--- OpenSP-1.5.2.orig/lib/OutputCharStream.cxx	2005-07-21 17:05:17.000000000 +0300
++++ OpenSP-1.5.2/lib/OutputCharStream.cxx	2014-08-24 17:23:19.957120700 +0300
+@@ -61,6 +61,13 @@
+   return *this << buf;
+ }
+ 
++OutputCharStream &OutputCharStream::operator<<(unsigned long long n)
++{
++  char buf[sizeof(unsigned long long)*3 + 1];
++  sprintf(buf, "%I64u", n);
++  return *this << buf;
++}
++
+ OutputCharStream &OutputCharStream::operator<<(int n)
+ {
+   char buf[sizeof(int)*3 + 2];
+diff -Nru -x '*~' OpenSP-1.5.2.orig/lib/SGMLApplication.cxx OpenSP-1.5.2/lib/SGMLApplication.cxx
+--- OpenSP-1.5.2.orig/lib/SGMLApplication.cxx	2005-07-21 17:05:18.000000000 +0300
++++ OpenSP-1.5.2/lib/SGMLApplication.cxx	2014-08-24 17:23:19.972745700 +0300
+@@ -9,6 +9,10 @@
+ #include "Boolean.h"
+ #include "SGMLApplication.h"
+ 
++SGMLApplication::SGMLApplication()
++{
++}
++
+ SGMLApplication::~SGMLApplication()
+ {
+ }
diff --git a/versions/baseline.json b/versions/baseline.json
index f334952134f54d..59cb5e6f637d61 100644
--- a/versions/baseline.json
+++ b/versions/baseline.json
@@ -3660,6 +3660,10 @@
       "baseline": "2017-01-28-cf2390140",
       "port-version": 2
     },
+    "libopensp": {
+      "baseline": "1.5.2",
+      "port-version": 0
+    },
     "libopusenc": {
       "baseline": "0.2.1",
       "port-version": 1
diff --git a/versions/l-/libopensp.json b/versions/l-/libopensp.json
new file mode 100644
index 00000000000000..168ab8b2513a97
--- /dev/null
+++ b/versions/l-/libopensp.json
@@ -0,0 +1,9 @@
+{
+  "versions": [
+    {
+      "git-tree": "c52391221569480b2e639b0e07a9e809e7711320",
+      "version": "1.5.2",
+      "port-version": 0
+    }
+  ]
+}