diff --git a/json_rpc.nimble b/json_rpc.nimble
index 03fa2d6..adec800 100644
--- a/json_rpc.nimble
+++ b/json_rpc.nimble
@@ -20,6 +20,8 @@ proc configForTests() =
   --run
   --forceBuild
   --threads: on
+  if hostOS == "windows":
+    --define: "chronicles_colors=NoColors"
 
 task test, "run tests":
   configForTests()