diff --git a/include/unifex/tracing/async_stack-inl.hpp b/include/unifex/tracing/async_stack-inl.hpp
index add04bde..99e84987 100644
--- a/include/unifex/tracing/async_stack-inl.hpp
+++ b/include/unifex/tracing/async_stack-inl.hpp
@@ -136,9 +136,10 @@ inline AsyncStackFrame* AsyncStackRoot::getTopFrame() const noexcept {
 }
 
 inline void AsyncStackRoot::setStackFrameContext(
-    frame_ptr framePtr, instruction_ptr ip) noexcept {
+    frame_ptr framePtr, instruction_ptr ip, uint64_t tId) noexcept {
   stackFramePtr = framePtr;
   returnAddress = ip;
+  threadId = tId;
 }
 
 inline frame_ptr AsyncStackRoot::getStackFramePointer() const noexcept {
diff --git a/include/unifex/tracing/async_stack.hpp b/include/unifex/tracing/async_stack.hpp
index ec7f67d6..e8702ce0 100644
--- a/include/unifex/tracing/async_stack.hpp
+++ b/include/unifex/tracing/async_stack.hpp
@@ -24,6 +24,15 @@
 #include <thread>
 
 #include <unifex/detail/prologue.hpp>
+#include <sys/syscall.h>
+
+#if defined(__APPLE__)
+#define UNIFEX_SYS_gettid SYS_thread_selfid
+#elif defined(SYS_gettid)
+#define UNIFEX_SYS_gettid SYS_gettid
+#else
+#define UNIFEX_SYS_gettid __NR_gettid
+#endif
 
 namespace unifex {
 
@@ -150,7 +159,11 @@ struct AsyncStackRoot;
 struct AsyncStackFrame;
 namespace detail {
 class ScopedAsyncStackRoot;
-}
+} // namespace detail
+
+namespace utils {
+  uint64_t getOSThreadID();
+} // namespace utils
 
 // Get access to the current thread's top-most AsyncStackRoot.
 //
@@ -454,7 +467,8 @@ struct AsyncStackRoot {
   // normal stack-trace.
   void setStackFrameContext(
       frame_ptr fp = frame_ptr::read_frame_pointer(),
-      instruction_ptr ip = instruction_ptr::read_return_address()) noexcept;
+      instruction_ptr ip = instruction_ptr::read_return_address(),
+      uint64_t tId = utils::getOSThreadID()) noexcept;
   frame_ptr getStackFramePointer() const noexcept;
   instruction_ptr getReturnAddress() const noexcept;
 
@@ -501,6 +515,7 @@ struct AsyncStackRoot {
   // Typically initialise with instruction_ptr::read_return_address() or
   // setStackFrameContext().
   instruction_ptr returnAddress;
+  uint64_t threadId = 0;
 };
 
 namespace detail {
diff --git a/source/async_stack.cpp b/source/async_stack.cpp
index 9cc0465b..4a2b5a99 100644
--- a/source/async_stack.cpp
+++ b/source/async_stack.cpp
@@ -145,6 +145,20 @@ static thread_local AsyncStackRootHolder currentThreadAsyncStackRoot;
 
 }  // namespace
 
+namespace utils {
+  uint64_t getOSThreadID() {
+  #if defined(__APPLE__)
+    uint64_t tid;
+    pthread_threadid_np(nullptr, &tid);
+    return tid;
+  #elif defined(_WIN32)
+    return uint64_t(GetCurrentThreadId());
+  #else
+    return uint64_t(syscall(UNIFEX_SYS_gettid));
+  #endif
+  }
+}
+
 AsyncStackRoot* tryGetCurrentAsyncStackRoot() noexcept {
   return currentThreadAsyncStackRoot.get();
 }