diff --git a/windows/init.cpp b/windows/init.cpp
index 2fb52c0f..6b6752da 100644
--- a/windows/init.cpp
+++ b/windows/init.cpp
@@ -140,6 +140,7 @@ const char *uiInit(uiInitOptions *o)
 
 void uiUninit(void)
 {
+	uiprivUninitTimers();
 	uiprivUninitImage();
 	uninitMenus();
 	unregisterD2DScratchClass();
diff --git a/windows/main.cpp b/windows/main.cpp
index d171e339..485ef570 100644
--- a/windows/main.cpp
+++ b/windows/main.cpp
@@ -129,6 +129,8 @@ void uiQueueMain(void (*f)(void *data), void *data)
 		logLastError(L"error queueing function to run on main thread");
 }
 
+static std::map<uiprivTimer *, bool> timers;
+
 void uiTimer(int milliseconds, int (*f)(void *data), void *data)
 {
 	uiprivTimer *timer;
@@ -139,4 +141,19 @@ void uiTimer(int milliseconds, int (*f)(void *data), void *data)
 	// note that timer IDs are pointer sized precisely so we can use them as timer IDs; see https://blogs.msdn.microsoft.com/oldnewthing/20150924-00/?p=91521
 	if (SetTimer(utilWindow, (UINT_PTR) timer, milliseconds, NULL) == 0)
 		logLastError(L"error calling SetTimer() in uiTimer()");
+	timers[timer] = true;
+}
+
+void uiprivFreeTimer(uiprivTimer *t)
+{
+	timers.erase(t);
+	uiprivFree(t);
+}
+
+void uiprivUninitTimers(void)
+{
+	// TODO why doesn't auto t : timers work?
+	for (auto t = timers.begin(); t != timers.end(); t++)
+		uiprivFree(t->first);
+	timers.clear();
 }
diff --git a/windows/uipriv_windows.hpp b/windows/uipriv_windows.hpp
index a1c2bc29..52d74c51 100644
--- a/windows/uipriv_windows.hpp
+++ b/windows/uipriv_windows.hpp
@@ -103,6 +103,8 @@ struct uiprivTimer {
 };
 extern int registerMessageFilter(void);
 extern void unregisterMessageFilter(void);
+extern void uiprivFreeTimer(uiprivTimer *t);
+extern void uiprivUninitTimers(void);
 
 // parent.cpp
 extern void paintContainerBackground(HWND hwnd, HDC dc, RECT *paintRect);
diff --git a/windows/utilwin.cpp b/windows/utilwin.cpp
index fc2d15d4..08183753 100644
--- a/windows/utilwin.cpp
+++ b/windows/utilwin.cpp
@@ -42,7 +42,7 @@ static LRESULT CALLBACK utilWindowWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, L
 		if (!(*(timer->f))(timer->data)) {
 			if (KillTimer(utilWindow, (UINT_PTR) timer) == 0)
 				logLastError(L"error calling KillTimer() to end uiTimer() procedure");
-			uiprivFree(timer);
+			uiprivFreeTimer(timer);
 		}
 		return 0;
 	}