diff --git a/chart/dev-sso-values.yaml b/chart/dev-sso-values.yaml
index 2235091ddb3985ea04550d47211d86b8159bf298..a16d3a430ed3f4be14641f5ae0761c46209f290d 100644
--- a/chart/dev-sso-values.yaml
+++ b/chart/dev-sso-values.yaml
@@ -75,3 +75,8 @@ addons:
     sso:
       enabled: true
       client_id: platform1_a8604cc9-f5e9-4656-802d-d05624370245_bb8-confluence
+  mattermost:
+    sso:
+      enabled: true
+      client_id: "platform1_a8604cc9-f5e9-4656-802d-d05624370245_bb8-mattermost"
+      client_secret: "no-secret"
diff --git a/chart/templates/mattermost/mattermost/mattermost-helmrelease.yaml b/chart/templates/mattermost/mattermost/mattermost-helmrelease.yaml
index b681ec9e4b60fdcb2fd8ce5db3464884be6ab175..82dc07bf639b7819ce7a81825cafdda08a611f25 100644
--- a/chart/templates/mattermost/mattermost/mattermost-helmrelease.yaml
+++ b/chart/templates/mattermost/mattermost/mattermost-helmrelease.yaml
@@ -52,7 +52,7 @@ spec:
     sso:
       enabled: {{ .enabled }}
       client_id: {{ .client_id }}
-      client_secret: {{ .client_secret }}
+      client_secret: {{ .client_secret | default "no-secret" }}
       auth_endpoint: {{ .auth_endpoint | default (printf "https://%s/oauth/authorize" $.Values.sso.oidc.host) }}
       token_endpoint: {{ .token_endpoint | default (printf "https://%s/oauth/token" $.Values.sso.oidc.host) }}
       user_api_endpoint: {{ .user_api_endpoint | default (printf "https://%s/api/v4/user" $.Values.sso.oidc.host) }}