diff --git a/sdk/lib/vcruntime/CMakeLists.txt b/sdk/lib/vcruntime/CMakeLists.txt
index 633a1b7a466..405dc705bd9 100644
--- a/sdk/lib/vcruntime/CMakeLists.txt
+++ b/sdk/lib/vcruntime/CMakeLists.txt
@@ -20,7 +20,6 @@ list(APPEND VCRT_COMMON_SOURCES
     __report_gsfailure.c
     __report_rangecheckfailure.c
     __security_init_cookie.c
-    __vcrt_init.c
     _fltused.c
     initializers.cpp
     isa_available.cpp
@@ -29,11 +28,13 @@ list(APPEND VCRT_COMMON_SOURCES
 
 list(APPEND VCRT_RUNTIME_SOURCES
     __std_terminate.c
+    __vcrt_init.c
 )
 
 list(APPEND VCRT_STARTUP_SOURCES
     __acrt_initialize_stub.cpp
     __scrt_uninitialize_crt.cpp
+    __vcrt_init_stubs.c
     mainCRTStartup.cpp
     wmainCRTStartup.cpp
 )
diff --git a/sdk/lib/vcruntime/__vcrt_init.c b/sdk/lib/vcruntime/__vcrt_init.c
index 45cce866e92..839c24de7e8 100644
--- a/sdk/lib/vcruntime/__vcrt_init.c
+++ b/sdk/lib/vcruntime/__vcrt_init.c
@@ -8,29 +8,64 @@
 // SPDX-License-Identifier: MIT
 //
 
-#include <vcruntime_startup.h>
+#include <internal_shared.h>
+
+void msvcrt_init_exception(HINSTANCE hinstDLL);
+BOOL msvcrt_init_tls(void);
+void msvcrt_free_tls_mem(void);
+BOOL msvcrt_free_tls(void);
 
 __vcrt_bool __cdecl __vcrt_initialize(void)
 {
-    return 1;
+    msvcrt_init_exception(GetModuleHandle(NULL));
+
+    if (!msvcrt_init_tls())
+        return FALSE;
+
+    return TRUE;
 }
 
 __vcrt_bool __cdecl __vcrt_uninitialize(_In_ __vcrt_bool _Terminating)
 {
-    return 1;
+    if (!msvcrt_free_tls())
+        return FALSE;
+
+    return TRUE;
 }
 
 __vcrt_bool __cdecl __vcrt_uninitialize_critical(void)
 {
-    return 1;
+    return TRUE;
 }
 
 __vcrt_bool __cdecl __vcrt_thread_attach(void)
 {
-    return 1;
+    // Not called by UCRT
+    return TRUE;
 }
 
 __vcrt_bool __cdecl __vcrt_thread_detach(void)
 {
-    return 1;
+    // Not called by UCRT
+    return TRUE;
 }
+
+// UCRT doesn't have a thread detach callback for the vcruntime TLS, because
+// the native vcruntime uses FlsAlloc and provides a cleanup callback there.
+// Since we don't have that, we use TLS callbacks.
+const IMAGE_TLS_DIRECTORY* __p_tls_used = &_tls_used;
+
+static
+VOID
+WINAPI
+wine_tls_cleanup_callback(PVOID hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
+{
+    // For the last thread, only DLL_PROCESS_DETACH is called
+    if ((fdwReason == DLL_THREAD_DETACH) ||
+        (fdwReason == DLL_PROCESS_DETACH))
+    {
+        msvcrt_free_tls_mem();
+    }
+}
+
+_CRTALLOC(".CRT$XLD") PIMAGE_TLS_CALLBACK wine_tls_cleanup_ptr = wine_tls_cleanup_callback;
diff --git a/sdk/lib/vcruntime/__vcrt_init_stubs.c b/sdk/lib/vcruntime/__vcrt_init_stubs.c
new file mode 100644
index 00000000000..3b01a3f119b
--- /dev/null
+++ b/sdk/lib/vcruntime/__vcrt_init_stubs.c
@@ -0,0 +1,36 @@
+//
+// __vcrt_init_stubs.c
+//
+//      Copyright (c) 2024 Timo Kreuzer
+//
+// Stubs for vcruntime initialization and termination in vcstartup.
+//
+// SPDX-License-Identifier: MIT
+//
+
+#include <vcruntime_startup.h>
+
+__vcrt_bool __cdecl __vcrt_initialize(void)
+{
+    return 1;
+}
+
+__vcrt_bool __cdecl __vcrt_uninitialize(_In_ __vcrt_bool _Terminating)
+{
+    return 1;
+}
+
+__vcrt_bool __cdecl __vcrt_uninitialize_critical(void)
+{
+    return 1;
+}
+
+__vcrt_bool __cdecl __vcrt_thread_attach(void)
+{
+    return 1;
+}
+
+__vcrt_bool __cdecl __vcrt_thread_detach(void)
+{
+    return 1;
+}