diff --git a/akka-stream-tests-tck/build.sbt b/akka-stream-tests-tck/build.sbt
index 72496d5c63..5097260b2d 100644
--- a/akka-stream-tests-tck/build.sbt
+++ b/akka-stream-tests-tck/build.sbt
@@ -6,3 +6,9 @@ Formatting.formatSettings
 Dependencies.streamTestsTck
 
 disablePlugins(MimaPlugin)
+
+// These TCK tests are using System.gc(), which
+// is causing long GC pauses when running with G1 on
+// the CI build servers. Therefore we fork these tests
+// to run with small heap without G1. 
+fork in Test := true