diff --git a/app/models/portal.rb b/app/models/portal.rb
index 9d2da6965..dfd5347aa 100644
--- a/app/models/portal.rb
+++ b/app/models/portal.rb
@@ -50,6 +50,13 @@ class Portal < ApplicationRecord
                  schema: PortalConfigSchema::CONFIG_PARAMS_SCHEMA,
                  attribute_resolver: ->(record) { record.config }
 
+  # Portal name/slug are embedded as help_center into the cached inbox payload
+  # (api/v1/models/_inbox.json.jbuilder), so portal changes must bump the
+  # account's inbox cache key. Destroy is covered too: dependent: :nullify
+  # detaches inboxes via update_all and skips their callbacks.
+  after_update_commit -> { account.update_cache_key('inbox') }
+  after_destroy_commit -> { account.update_cache_key('inbox') }
+
   scope :active, -> { where(archived: false) }
 
   # TODO: 'website_token' is an unused reserved key; remove with a migration that scrubs it from existing portals' config
diff --git a/spec/models/portal_spec.rb b/spec/models/portal_spec.rb
index c71a458fd..ce58da652 100644
--- a/spec/models/portal_spec.rb
+++ b/spec/models/portal_spec.rb
@@ -150,4 +150,22 @@ RSpec.describe Portal do
       expect(portal.display_title).to eq('Help Center | Acme')
     end
   end
+
+  describe 'inbox cache invalidation' do
+    # Portal name/slug are embedded as help_center into the cached inbox
+    # payload (api/v1/models/_inbox.json.jbuilder), so portal changes must bump
+    # the account's inbox cache key.
+    let(:account) { create(:account) }
+    let!(:portal) { create(:portal, account: account) }
+
+    it 'bumps the inbox cache key after update' do
+      expect(account).to receive(:update_cache_key).with('inbox')
+      portal.update!(name: 'Renamed Portal')
+    end
+
+    it 'bumps the inbox cache key after destroy' do
+      expect(account).to receive(:update_cache_key).with('inbox')
+      portal.destroy!
+    end
+  end
 end