diff --git a/clang-tools-extra/clang-tidy/tool/CMakeLists.txt b/clang-tools-extra/clang-tidy/tool/CMakeLists.txt
--- a/clang-tools-extra/clang-tidy/tool/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/tool/CMakeLists.txt
@@ -29,11 +29,17 @@
   clangToolingCore
   )
 
+# Support plugins.
+if(CLANG_PLUGIN_SUPPORT)
+  set(support_plugins SUPPORT_PLUGINS)
+endif()
+
 add_clang_tool(clang-tidy
   ClangTidyToolMain.cpp
-  )
-add_dependencies(clang-tidy
+
+  DEPENDS
   clang-resource-headers
+  ${support_plugins}
   )
 clang_target_link_libraries(clang-tidy
   PRIVATE
@@ -50,6 +56,9 @@
   ${ALL_CLANG_TIDY_CHECKS}
   )
 
+if(CLANG_PLUGIN_SUPPORT)
+  export_executable_symbols_for_plugins(clang-tidy)
+endif()
 
 install(PROGRAMS clang-tidy-diff.py
   DESTINATION share/clang
diff --git a/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp b/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
--- a/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
+++ b/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
@@ -20,6 +20,7 @@
 #include "../GlobList.h"
 #include "clang/Tooling/CommonOptionsParser.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/PluginLoader.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/TargetSelect.h"
@@ -386,6 +387,12 @@
 
 int clangTidyMain(int argc, const char **argv) {
   llvm::InitLLVM X(argc, argv);
+
+  // Enable help for -load option, if plugins are enabled.
+  cl::Option *load_opt = cl::getRegisteredOptions().lookup("load");
+  if (load_opt)
+    load_opt->addCategory(ClangTidyCategory);
+
   llvm::Expected<CommonOptionsParser> OptionsParser =
       CommonOptionsParser::create(argc, argv, ClangTidyCategory,
                                   cl::ZeroOrMore);
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -73,6 +73,8 @@
 - Added support for `NOLINTBEGIN` ... `NOLINTEND` comments to suppress
   Clang-Tidy warnings over multiple lines.
 
+- Added support for external plugin checks with `-load`.
+
 New checks
 ^^^^^^^^^^
 
diff --git a/clang-tools-extra/docs/clang-tidy/Contributing.rst b/clang-tools-extra/docs/clang-tidy/Contributing.rst
--- a/clang-tools-extra/docs/clang-tidy/Contributing.rst
+++ b/clang-tools-extra/docs/clang-tidy/Contributing.rst
@@ -415,6 +415,21 @@
 .. _FileCheck: https://llvm.org/docs/CommandGuide/FileCheck.html
 .. _test/clang-tidy/google-readability-casting.cpp: https://reviews.llvm.org/diffusion/L/browse/clang-tools-extra/trunk/test/clang-tidy/google-readability-casting.cpp
 
+Out-of-tree check plugins
+-------------------------
+
+If you want to develop this out-of-tree, the steps above are the largely same.
+External to the clang-tidy build system, put all of the new code into a single
+shared library. Build and link it against llvm, while allowing some symbols to
+be undefined during linking, almost exactly as you would define a clang plugin.
+
+Then we can run it by passing `-load` to `clang-tidy`, in addition to the name
+of our new checks.
+
+.. code-block:: console
+
+  $ clang-tidy --checks=-*,my-explicit-constructor -list-checks -load myplugin.so
+
 
 Running clang-tidy on LLVM
 --------------------------
diff --git a/clang-tools-extra/docs/clang-tidy/index.rst b/clang-tools-extra/docs/clang-tidy/index.rst
--- a/clang-tools-extra/docs/clang-tidy/index.rst
+++ b/clang-tools-extra/docs/clang-tidy/index.rst
@@ -218,6 +218,14 @@
     --list-checks                  -
                                      List all enabled checks and exit. Use with
                                      -checks=* to list all available checks.
+    -load=<plugin>                 -
+                                     Load the dynamic object ``plugin``. This
+                                     object should register new static analyzer or clang-tidy passes. Once loaded, the object
+                                     will add new command line options to run
+                                     various analyses. To see the new complete
+                                     list of passes, use the
+                                     :option:`--list-checks` and
+                                     :option:`-load` options together.
     -p=<string>                    - Build path
     --quiet                        -
                                      Run clang-tidy in quiet mode. This suppresses
diff --git a/clang-tools-extra/test/CMakeLists.txt b/clang-tools-extra/test/CMakeLists.txt
--- a/clang-tools-extra/test/CMakeLists.txt
+++ b/clang-tools-extra/test/CMakeLists.txt
@@ -17,6 +17,7 @@
 
 llvm_canonicalize_cmake_booleans(
   CLANG_TIDY_ENABLE_STATIC_ANALYZER
+  LLVM_ENABLE_PLUGINS
   )
 
 configure_lit_site_cfg(
@@ -78,6 +79,22 @@
   endif()
 endforeach()
 
+llvm_add_library(
+    CTTestTidyModule
+    MODULE clang-tidy/CTTestTidyModule.cpp
+    PLUGIN_TOOL clang-tidy
+    DEPENDS clang-tidy-headers)
+
+if(TARGET CTTestTidyModule)
+    list(APPEND CLANG_TOOLS_TEST_DEPS CTTestTidyModule)
+    target_include_directories(CTTestTidyModule PUBLIC BEFORE "${CLANG_TOOLS_SOURCE_DIR}")
+    if(LLVM_ENABLE_PLUGINS AND (WIN32 OR CYGWIN))
+      set(LLVM_LINK_COMPONENTS
+        Support
+      )
+    endif()
+endif()
+
 add_lit_testsuite(check-clang-tools "Running the Clang extra tools' regression tests"
   ${CMAKE_CURRENT_BINARY_DIR}
   DEPENDS ${CLANG_TOOLS_TEST_DEPS}
diff --git a/clang-tools-extra/test/clang-tidy/CTTestTidyModule.cpp b/clang-tools-extra/test/clang-tidy/CTTestTidyModule.cpp
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/CTTestTidyModule.cpp
@@ -0,0 +1,50 @@
+// REQUIRES: plugins
+// RUN: clang-tidy -checks='-*,mytest' --list-checks -load %llvmshlibdir/CTTestTidyModule%pluginext | FileCheck %s
+// CHECK: Enabled checks:
+// CHECK-NEXT:    mytest
+
+#include "clang-tidy/ClangTidy.h"
+#include "clang-tidy/ClangTidyCheck.h"
+#include "clang-tidy/ClangTidyModule.h"
+#include "clang-tidy/ClangTidyModuleRegistry.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang;
+using namespace clang::tidy;
+using namespace clang::ast_matchers;
+
+namespace {
+class MyTestCheck : public ClangTidyCheck {
+
+public:
+  MyTestCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+
+  //void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  //void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+};
+
+class CTTestModule : public ClangTidyModule {
+public:
+  void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
+    CheckFactories.registerCheck<MyTestCheck>("mytest");
+  }
+};
+} // namespace
+
+namespace clang {
+namespace tidy {
+
+// Register the CTTestTidyModule using this statically initialized variable.
+static ClangTidyModuleRegistry::Add<::CTTestModule>
+    X("mytest-module", "Adds my checks.");
+
+// This anchor is used to force the linker to link in the generated object file
+// and thus register the CTTestModule.
+volatile int CTTestModuleAnchorSource = 0;
+
+} // namespace tidy
+} // namespace clang
diff --git a/clang-tools-extra/test/lit.cfg.py b/clang-tools-extra/test/lit.cfg.py
--- a/clang-tools-extra/test/lit.cfg.py
+++ b/clang-tools-extra/test/lit.cfg.py
@@ -149,3 +149,9 @@
                                      "clangd", "benchmarks")
 config.substitutions.append(('%clangd-benchmark-dir',
                              '%s' % (clangd_benchmarks_dir)))
+config.substitutions.append(('%llvmshlibdir', config.clang_libs_dir))
+config.substitutions.append(('%pluginext', config.llvm_plugin_ext))
+
+# Plugins (loadable modules)
+if config.has_plugins and config.llvm_plugin_ext:
+    config.available_features.add('plugins')
diff --git a/clang-tools-extra/test/lit.site.cfg.py.in b/clang-tools-extra/test/lit.site.cfg.py.in
--- a/clang-tools-extra/test/lit.site.cfg.py.in
+++ b/clang-tools-extra/test/lit.site.cfg.py.in
@@ -4,6 +4,7 @@
 
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
 config.llvm_libs_dir = "@LLVM_LIBS_DIR@"
+config.llvm_plugin_ext = "@LLVM_PLUGIN_EXT@"
 config.lit_tools_dir = "@LLVM_LIT_TOOLS_DIR@"
 config.clang_tools_binary_dir = "@CLANG_TOOLS_BINARY_DIR@"
 config.clang_tools_dir = "@CLANG_TOOLS_DIR@"
@@ -11,6 +12,7 @@
 config.python_executable = "@Python3_EXECUTABLE@"
 config.target_triple = "@TARGET_TRIPLE@"
 config.clang_tidy_staticanalyzer = @CLANG_TIDY_ENABLE_STATIC_ANALYZER@
+config.has_plugins = @LLVM_ENABLE_PLUGINS@
 
 # Support substitution of the tools and libs dirs with user parameters. This is
 # used when we can't determine the tool dir at configuration time.