diff --git a/cmd/dex/serve.go b/cmd/dex/serve.go
index 74141158..1d3389e8 100644
--- a/cmd/dex/serve.go
+++ b/cmd/dex/serve.go
@@ -614,6 +614,7 @@ func applyConfigOverrides(options serveOptions, config *Config) {
 	if len(config.OAuth2.GrantTypes) == 0 {
 		config.OAuth2.GrantTypes = []string{
 			"authorization_code",
+			"client_credentials",
 			"implicit",
 			"password",
 			"refresh_token",