diff --git a/lib/thread/_linux_arm.q b/lib/thread/_linux_arm.q
index 49f513a..68a60f2 100644
--- a/lib/thread/_linux_arm.q
+++ b/lib/thread/_linux_arm.q
@@ -1,3 +1,4 @@
 const {
 	_exit = 93
+	_gettid = 178
 }
\ No newline at end of file
diff --git a/lib/thread/_linux_x86.q b/lib/thread/_linux_x86.q
index 8f015db..dc95e45 100644
--- a/lib/thread/_linux_x86.q
+++ b/lib/thread/_linux_x86.q
@@ -1,3 +1,4 @@
 const {
 	_exit = 60
+	_gettid = 186
 }
\ No newline at end of file
diff --git a/lib/thread/id_linux.q b/lib/thread/id_linux.q
new file mode 100644
index 0000000..c2ab077
--- /dev/null
+++ b/lib/thread/id_linux.q
@@ -0,0 +1,3 @@
+id() -> int {
+	return syscall(_gettid)
+}
\ No newline at end of file
diff --git a/lib/thread/id_mac.q b/lib/thread/id_mac.q
new file mode 100644
index 0000000..8bbd62a
--- /dev/null
+++ b/lib/thread/id_mac.q
@@ -0,0 +1,6 @@
+import io
+
+id() -> int {
+	io.write("thread.id: not implemented on Mac\n")
+	return 0
+}
\ No newline at end of file
diff --git a/lib/thread/id_windows.q b/lib/thread/id_windows.q
new file mode 100644
index 0000000..3f314b8
--- /dev/null
+++ b/lib/thread/id_windows.q
@@ -0,0 +1,9 @@
+id() -> int {
+	return kernel32.GetCurrentThreadId()
+}
+
+extern {
+	kernel32 {
+		GetCurrentThreadId() -> int
+	}
+}
\ No newline at end of file