diff --git a/tools/internal_ci/linux/grpc_interop.cfg b/tools/internal_ci/linux/grpc_interop.cfg
index ecafcf62ae9..23b83d2f91e 100644
--- a/tools/internal_ci/linux/grpc_interop.cfg
+++ b/tools/internal_ci/linux/grpc_interop.cfg
@@ -32,7 +32,8 @@
 
 # Location of the continuous shell script in repository.
 build_file: "grpc/tools/internal_ci/linux/grpc_interop.sh"
-timeout_mins: 60
+# grpc_interop tests can take MANY hours to complete.
+timeout_mins: 480
 action {
   define_artifacts {
     regex: "**/sponge_log.xml"