diff --git a/ttcn3/ttcn3.sh b/ttcn3/ttcn3.sh
index 42bc095..3c468d4 100755
--- a/ttcn3/ttcn3.sh
+++ b/ttcn3/ttcn3.sh
@@ -247,8 +247,10 @@ build_testsuite() {
 	# since we will run it inside docker later too.
 	local hacks="${DIR_OSMODEV}/src/osmo-ttcn3-hacks"
 
+	# -t: add a tty, so we get color output from the compiler
 	docker run \
 		--rm \
+		-t \
 		-v "$hacks:/osmo-ttcn3-hacks" \
 		"$(get_testsuite_image)" \
 		sh -exc "