diff --git a/private/private.h b/private/private.h
index 7fba396e1..19ccccddb 100644
--- a/private/private.h
+++ b/private/private.h
@@ -182,7 +182,7 @@ void _dispatch_prohibit_transition_to_multithreaded(bool prohibit);
 #define DISPATCH_COCOA_COMPAT 0
 #endif
 
-#if DISPATCH_COCOA_COMPAT
+#if DISPATCH_COCOA_COMPAT || defined(_WIN32)
 
 #define DISPATCH_CF_SPI_VERSION 20160712
 
@@ -190,6 +190,8 @@ void _dispatch_prohibit_transition_to_multithreaded(bool prohibit);
 typedef mach_port_t dispatch_runloop_handle_t;
 #elif defined(__linux__) || defined(__FreeBSD__)
 typedef int dispatch_runloop_handle_t;
+#elif defined(_WIN32)
+typedef void *dispatch_runloop_handle_t;
 #else
 #error "runloop support not implemented on this platform"
 #endif
@@ -218,12 +220,14 @@ dispatch_queue_t
 _dispatch_runloop_root_queue_create_4CF(const char *_Nullable label,
 		unsigned long flags);
 
-#if TARGET_OS_MAC
+#if TARGET_OS_MAC || defined(_WIN32)
 API_AVAILABLE(macos(10.9), ios(7.0))
 DISPATCH_EXPORT DISPATCH_WARN_RESULT DISPATCH_NOTHROW
-mach_port_t
+dispatch_runloop_handle_t
 _dispatch_runloop_root_queue_get_port_4CF(dispatch_queue_t queue);
+#endif
 
+#if TARGET_OS_MAC
 #ifdef __BLOCKS__
 API_AVAILABLE(macos(10.12), ios(10.0), tvos(10.0), watchos(3.0))
 DISPATCH_EXPORT DISPATCH_MALLOC DISPATCH_RETURNS_RETAINED DISPATCH_WARN_RESULT
@@ -259,7 +263,7 @@ API_AVAILABLE(macos(10.6), ios(4.0))
 DISPATCH_EXPORT
 void (*_Nullable _dispatch_end_NSAutoReleasePool)(void *);
 
-#endif /* DISPATCH_COCOA_COMPAT */
+#endif /* DISPATCH_COCOA_COMPAT || defined(_WIN32) */
 
 API_AVAILABLE(macos(10.12), ios(10.0), tvos(10.0), watchos(3.0))
 DISPATCH_EXPORT DISPATCH_NOTHROW
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 4790ac6d9..4da1b3f15 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -63,7 +63,6 @@ if(WIN32)
   target_sources(dispatch
                  PRIVATE
                    shims/generic_sys_queue.h
-                   shims/generic_win_stubs.c
                    shims/generic_win_stubs.h
                    shims/getprogname.c)
 endif()
diff --git a/src/queue.c b/src/queue.c
index b1b4458f9..adb1e1cca 100644
--- a/src/queue.c
+++ b/src/queue.c
@@ -93,10 +93,14 @@ _dispatch_worker_thread_thunk(LPVOID lpParameter);
 #endif
 #endif
 
-#if DISPATCH_COCOA_COMPAT
+#if DISPATCH_COCOA_COMPAT || defined(_WIN32)
 static dispatch_once_t _dispatch_main_q_handle_pred;
+#endif
+#if DISPATCH_COCOA_COMPAT
 static void _dispatch_runloop_queue_poke(dispatch_queue_t dq,
 		dispatch_qos_t qos, dispatch_wakeup_flags_t flags);
+#endif
+#if DISPATCH_COCOA_COMPAT || defined(_WIN32)
 static void _dispatch_runloop_queue_handle_init(void *ctxt);
 static void _dispatch_runloop_queue_handle_dispose(dispatch_queue_t dq);
 #endif
@@ -4476,7 +4480,7 @@ _dispatch_queue_wakeup(dispatch_queue_t dq, dispatch_qos_t qos,
 	return _dispatch_queue_class_wakeup(dq, qos, flags, target);
 }
 
-#if DISPATCH_COCOA_COMPAT
+#if DISPATCH_COCOA_COMPAT || defined(_WIN32)
 DISPATCH_ALWAYS_INLINE
 static inline bool
 _dispatch_runloop_handle_is_valid(dispatch_runloop_handle_t handle)
@@ -4485,6 +4489,8 @@ _dispatch_runloop_handle_is_valid(dispatch_runloop_handle_t handle)
 	return MACH_PORT_VALID(handle);
 #elif defined(__linux__)
 	return handle >= 0;
+#elif defined(_WIN32)
+	return handle != INVALID_HANDLE_VALUE;
 #else
 #error "runloop support not implemented on this platform"
 #endif
@@ -4499,6 +4505,8 @@ _dispatch_runloop_queue_get_handle(dispatch_queue_t dq)
 #elif defined(__linux__)
 	// decode: 0 is a valid fd, so offset by 1 to distinguish from NULL
 	return ((dispatch_runloop_handle_t)(uintptr_t)dq->do_ctxt) - 1;
+#elif defined(_WIN32)
+	return ((dispatch_runloop_handle_t)(uintptr_t)dq->do_ctxt);
 #else
 #error "runloop support not implemented on this platform"
 #endif
@@ -4513,6 +4521,8 @@ _dispatch_runloop_queue_set_handle(dispatch_queue_t dq, dispatch_runloop_handle_
 #elif defined(__linux__)
 	// encode: 0 is a valid fd, so offset by 1 to distinguish from NULL
 	dq->do_ctxt = (void *)(uintptr_t)(handle + 1);
+#elif defined(_WIN32)
+	dq->do_ctxt = (void *)(uintptr_t)handle;
 #else
 #error "runloop support not implemented on this platform"
 #endif
@@ -4527,7 +4537,7 @@ _dispatch_runloop_queue_reset_max_qos(dispatch_queue_class_t dqu)
 	old_state = os_atomic_and_orig2o(dqu._dq, dq_state, ~clear_bits, relaxed);
 	return _dq_state_max_qos(old_state);
 }
-#endif // DISPATCH_COCOA_COMPAT
+#endif
 
 void
 _dispatch_runloop_queue_wakeup(dispatch_queue_t dq, dispatch_qos_t qos,
@@ -5112,7 +5122,7 @@ _dispatch_queue_serial_drain(dispatch_queue_t dq, dispatch_invoke_context_t dic,
 	return _dispatch_queue_drain(dq, dic, flags, owned, true);
 }
 
-#if DISPATCH_COCOA_COMPAT
+#if DISPATCH_COCOA_COMPAT || defined(_WIN32)
 DISPATCH_NOINLINE
 static void
 _dispatch_main_queue_update_priority_from_thread(void)
@@ -6178,7 +6188,7 @@ _dispatch_network_root_queue_create_4NW(const char *label,
 
 static bool _dispatch_program_is_probably_callback_driven;
 
-#if DISPATCH_COCOA_COMPAT
+#if DISPATCH_COCOA_COMPAT || defined(_WIN32)
 
 dispatch_queue_t
 _dispatch_runloop_root_queue_create_4CF(const char *label, unsigned long flags)
@@ -6242,7 +6252,7 @@ _dispatch_runloop_root_queue_wakeup_4CF(dispatch_queue_t dq)
 	_dispatch_runloop_queue_wakeup(dq, 0, false);
 }
 
-#if TARGET_OS_MAC
+#if TARGET_OS_MAC || defined(_WIN32)
 dispatch_runloop_handle_t
 _dispatch_runloop_root_queue_get_port_4CF(dispatch_queue_t dq)
 {
@@ -6305,6 +6315,8 @@ _dispatch_runloop_queue_handle_init(void *ctxt)
 		}
 	}
 	handle = fd;
+#elif defined(_WIN32)
+	handle = INVALID_HANDLE_VALUE;
 #else
 #error "runloop support not implemented on this platform"
 #endif
@@ -6332,6 +6344,8 @@ _dispatch_runloop_queue_handle_dispose(dispatch_queue_t dq)
 #elif defined(__linux__)
 	int rc = close(handle);
 	(void)dispatch_assume_zero(rc);
+#elif defined(_WIN32)
+	CloseHandle(handle);
 #else
 #error "runloop support not implemented on this platform"
 #endif
diff --git a/src/shims/generic_win_stubs.c b/src/shims/generic_win_stubs.c
deleted file mode 100644
index 67b6f5134..000000000
--- a/src/shims/generic_win_stubs.c
+++ /dev/null
@@ -1,24 +0,0 @@
-#include "internal.h"
-
-/*
- * This file contains stubbed out functions we are using during
- * the initial Windows port.  When the port is complete, this file
- * should be empty (and thus removed).
- */
-
-void
-_dispatch_runloop_queue_dispose(dispatch_queue_t dq DISPATCH_UNUSED,
-		bool *allow_free DISPATCH_UNUSED)
-{
-	WIN_PORT_ERROR();
-}
-
-void
-_dispatch_runloop_queue_xref_dispose(dispatch_queue_t dq DISPATCH_UNUSED)
-{
-	WIN_PORT_ERROR();
-}
-
-/*
- * Stubbed out static data
- */
diff --git a/src/swift/DispatchStubs.cc b/src/swift/DispatchStubs.cc
index 594f66648..0625cc91f 100644
--- a/src/swift/DispatchStubs.cc
+++ b/src/swift/DispatchStubs.cc
@@ -13,7 +13,11 @@
 #include <dispatch/dispatch.h>
 #include <stdio.h>
 
+#if defined(__ELF__) || defined(__MACH__) || defined(__WASM__)
 #define DISPATCH_RUNTIME_STDLIB_INTERFACE __attribute__((__visibility__("default")))
+#else
+#define DISPATCH_RUNTIME_STDLIB_INTERFACE __declspec(dllexport)
+#endif
 
 #if USE_OBJC
 @protocol OS_dispatch_source;
@@ -54,6 +58,7 @@ static void _dispatch_overlay_constructor() {
 #endif /* USE_OBJC */
 
 #if !USE_OBJC
+DISPATCH_RUNTIME_STDLIB_INTERFACE
 extern "C" void * objc_retainAutoreleasedReturnValue(void *obj);
 #endif