diff --git a/testing/btest/broker/remote_event_ts_compat.zeek b/testing/btest/broker/remote_event_ts_compat.zeek
index 8e73b1078c..d18b0579ca 100644
--- a/testing/btest/broker/remote_event_ts_compat.zeek
+++ b/testing/btest/broker/remote_event_ts_compat.zeek
@@ -7,6 +7,8 @@
 # @TEST-REQUIRES: TOPIC=/zeek/my_topic python3 client.py check
 #
 # @TEST-EXEC: TOPIC=/zeek/my_topic btest-bg-run server "zeek %INPUT >output"
+# Leave room for Zeek to start up, which can be slow when using -O ZAM
+# @TEST-EXEC: sleep 5
 # @TEST-EXEC: TOPIC=/zeek/my_topic btest-bg-run client "python3 ../client.py >output"
 #
 # @TEST-EXEC: btest-bg-wait 45