diff --git a/contrib/completion/bash/docker b/contrib/completion/bash/docker
index 08eb8c6cb3..4bfeb88990 100644
--- a/contrib/completion/bash/docker
+++ b/contrib/completion/bash/docker
@@ -2851,6 +2851,7 @@ _docker_service_update() {
 
 	local boolean_options="
 		--help
+		--read-only
 		--tty -t
 		--with-registry-auth
 	"
diff --git a/contrib/completion/zsh/_docker b/contrib/completion/zsh/_docker
index a76414c921..22e3a319cf 100644
--- a/contrib/completion/zsh/_docker
+++ b/contrib/completion/zsh/_docker
@@ -1795,6 +1795,7 @@ __docker_service_subcommand() {
         "($help)*--network=[Network attachments]:network: "
         "($help)--no-healthcheck[Disable any container-specified HEALTHCHECK]"
         "($help)*"{-p=,--publish=}"[Publish a port as a node port]:port: "
+        "($help)--read-only[Mount the container's root filesystem as read only]"
         "($help)--replicas=[Number of tasks]:replicas: "
         "($help)--reserve-cpu=[Reserve CPUs]:value: "
         "($help)--reserve-memory=[Reserve Memory]:value: "