diff --git a/scripts/dag_traversal.py b/scripts/dag_traversal.py
index d0c3cf6e50c5be..353f1698be6a91 100755
--- a/scripts/dag_traversal.py
+++ b/scripts/dag_traversal.py
@@ -46,6 +46,15 @@
 SHOW_CURSOR = "\033[?25h"
 
 
+
+def _kill_tree(proc: subprocess.Popen) -> None:
+    """Kill a build and all its children (`os.killpg` does not exist on Windows)."""
+    if hasattr(os, "killpg"):
+        os.killpg(proc.pid, signal.SIGKILL)
+    else:
+        subprocess.run(["taskkill", "/F", "/T", "/PID", str(proc.pid)],
+                       capture_output=True)
+
 class ShutdownError(Exception):
     """Raised when a shutdown has been requested (e.g. Ctrl-C)."""
 
@@ -98,7 +107,7 @@ def _kill_builds(self):
         with self._active_builds_lock:
             for proc in self._active_builds:
                 try:
-                    os.killpg(proc.pid, signal.SIGKILL)
+                    _kill_tree(proc)
                 except (ProcessLookupError, PermissionError):
                     try:
                         proc.kill()
@@ -160,7 +169,7 @@ def lake_build(
                 self._active_builds.discard(proc)
             if proc.poll() is None:
                 try:
-                    os.killpg(proc.pid, signal.SIGKILL)
+                    _kill_tree(proc)
                 except (ProcessLookupError, PermissionError):
                     proc.kill()
                 proc.wait()