diff --git a/core/testing/runner_other.odin b/core/testing/runner_other.odin
index f3271d2090a..86e1dda2c22 100644
--- a/core/testing/runner_other.odin
+++ b/core/testing/runner_other.odin
@@ -1,5 +1,10 @@
 //+private
 //+build !windows
+//+build !linux
+//+build !darwin
+//+build !freebsd
+//+build !openbsd
+//+build !haiku
 package testing
 
 import "core:time"
diff --git a/core/testing/runner_unix.odin b/core/testing/runner_unix.odin
new file mode 100644
index 00000000000..a3285cf3df8
--- /dev/null
+++ b/core/testing/runner_unix.odin
@@ -0,0 +1,83 @@
+//+private
+//+build linux, darwin, freebsd, openbsd, haiku
+package testing
+
+import "base:runtime"
+import "core:sync"
+import "core:thread"
+import "core:time"
+
+Runner_Thread_Data :: struct {
+	t: ^T,
+	it: Internal_Test,
+}
+
+Watcher_Thread_Data :: struct {
+	t: ^T,
+	duration: time.Duration,
+	loc: runtime.Source_Code_Location,
+}
+
+global_timeout_futex: sync.Futex
+
+run_internal_test :: proc(t: ^T, it: Internal_Test) {
+	runner := thread.create(proc(runner: ^thread.Thread) {
+		data := cast(^Runner_Thread_Data)runner.data
+
+		// Run the test.
+		data.it.p(data.t)
+
+		// Test completed; tell the main and watcher thread to continue.
+		sync.futex_broadcast(&global_timeout_futex)
+	})
+
+	// This data can live on the stack, since it will outlive the runner
+	// thread.
+	data: Runner_Thread_Data = {t, it}
+	runner.data = &data
+
+	thread.start(runner)
+
+	// Wait for either the runner thread to finish or the watcher thread to
+	// broadcast a failure.
+	sync.futex_wait(&global_timeout_futex, 0)
+
+	if !thread.is_done(runner) {
+		// The runner thread is still going, which means it's been timed out;
+		// forcibly terminate it.
+		thread.terminate(runner, 1)
+	}
+
+	// Destroy the runner thread and join it to this thread.
+	thread.destroy(runner)
+}
+
+_fail_timeout :: proc(t: ^T, duration: time.Duration, loc := #caller_location) {
+	watcher := thread.create(proc(watcher: ^thread.Thread) {
+		data := cast(^Watcher_Thread_Data)watcher.data
+
+		// Wait for either a timeout or the runner thread to clear us.
+		ok := sync.futex_wait_with_timeout(&global_timeout_futex, 0, data.duration)
+
+		if !ok {
+			// If the wait went beyond the duration, we tell the test suite
+			// that the test failed.
+			fail_now(data.t, "TIMEOUT", data.loc)
+		}
+
+		// Tell the main thread to resume operation.
+		sync.futex_broadcast(&global_timeout_futex)
+
+		// Cleanup allocations.
+		free(watcher.data)
+		thread.destroy(watcher)
+	})
+
+	// Allocate a new struct for this data, because it will live longer than
+	// the scope of this procedure.
+	ftd := new(Watcher_Thread_Data)
+	ftd^ = {t, duration, loc} 
+	watcher.data = ftd
+
+	thread.start(watcher)
+}