diff --git a/backend/migrations/core/098_add_email_template_category.js b/backend/migrations/core/098_add_email_template_category.js
new file mode 100644
index 00000000..e21806d1
--- /dev/null
+++ b/backend/migrations/core/098_add_email_template_category.js
@@ -0,0 +1,95 @@
+/**
+ * Migration: Categorise email templates + link them to feature flags.
+ *
+ * Adds two metadata columns to `email_templates`:
+ *
+ *   - `category` — display group in the admin Templates UI. One of:
+ *       'core'      — gallery delivery, admin, system, backups.
+ *                     Always visible, no feature flag.
+ *       'customers' — customer-portal lifecycle (invitation, etc.).
+ *       'billing'   — Bills feature (#354, not yet built).
+ *       'quotes'    — Quotes feature (#354, not yet built).
+ *       'calendar'  — Calendar feature (#354, not yet built).
+ *     Values outside this set are accepted (forward-compat) but the
+ *     UI will lump them under 'core' for now.
+ *
+ *   - `feature_flag` — name of the feature flag whose `false` value
+ *     should mark this template as "Feature off" in the admin UI.
+ *     NULL means the template is always active (gallery delivery,
+ *     admin lifecycle, system notifications).
+ *
+ * Categorisation does NOT hide templates. Disabled-feature templates
+ * stay visible and editable so admins can prep them before a feature
+ * launch; the UI shows a small "Feature off" chip on the entry.
+ *
+ * Idempotent: re-runs are no-ops.
+ */
+
+exports.up = async function(knex) {
+  if (!(await knex.schema.hasTable('email_templates'))) return;
+
+  const hasCategory = await knex.schema.hasColumn('email_templates', 'category');
+  if (!hasCategory) {
+    await knex.schema.alterTable('email_templates', (table) => {
+      // Default 'core' so existing rows aren't NULL; the backfill below
+      // overrides for templates that belong to a feature group.
+      table.string('category', 32).notNullable().defaultTo('core');
+    });
+  }
+
+  const hasFeatureFlag = await knex.schema.hasColumn('email_templates', 'feature_flag');
+  if (!hasFeatureFlag) {
+    await knex.schema.alterTable('email_templates', (table) => {
+      table.string('feature_flag', 64).nullable();
+    });
+  }
+
+  // Backfill — keyed by template_key so we don't accidentally update
+  // a row that's been renamed. Templates not in this map keep the
+  // 'core' / NULL defaults from the column definitions above.
+  const TEMPLATE_METADATA = {
+    // Core galleries — always-on, no flag.
+    gallery_created:               { category: 'core',      feature_flag: null },
+    expiration_warning:            { category: 'core',      feature_flag: null },
+    gallery_expired:               { category: 'core',      feature_flag: null },
+    archive_complete:              { category: 'core',      feature_flag: null },
+    // Admin / RBAC — always-on (admin login is foundational).
+    admin_invitation:              { category: 'core',      feature_flag: null },
+    admin_password_reset:          { category: 'core',      feature_flag: null },
+    // System — backups, restores, version-update notifications.
+    database_backup_completed:     { category: 'core',      feature_flag: null },
+    database_backup_failed:        { category: 'core',      feature_flag: null },
+    restore_completed:             { category: 'core',      feature_flag: null },
+    restore_failed:                { category: 'core',      feature_flag: null },
+    backup_completed:              { category: 'core',      feature_flag: null },
+    backup_failed:                 { category: 'core',      feature_flag: null },
+    version_update_available:      { category: 'core',      feature_flag: null },
+    version_update_test:           { category: 'core',      feature_flag: null },
+    // Customer portal (#354). customer_invitation is the only template
+    // here today; calendar / quotes / bills get their templates added
+    // when those features ship.
+    customer_invitation:           { category: 'customers', feature_flag: 'customerPortal' },
+  };
+
+  for (const [key, meta] of Object.entries(TEMPLATE_METADATA)) {
+    await knex('email_templates')
+      .where({ template_key: key })
+      .update({ category: meta.category, feature_flag: meta.feature_flag });
+  }
+};
+
+exports.down = async function(knex) {
+  if (!(await knex.schema.hasTable('email_templates'))) return;
+
+  if (await knex.schema.hasColumn('email_templates', 'feature_flag')) {
+    await knex.schema.alterTable('email_templates', (table) => {
+      table.dropColumn('feature_flag');
+    });
+  }
+
+  if (await knex.schema.hasColumn('email_templates', 'category')) {
+    await knex.schema.alterTable('email_templates', (table) => {
+      table.dropColumn('category');
+    });
+  }
+};
diff --git a/backend/src/routes/adminEmail.js b/backend/src/routes/adminEmail.js
index 19b236c5..8fb8a2c5 100644
--- a/backend/src/routes/adminEmail.js
+++ b/backend/src/routes/adminEmail.js
@@ -315,6 +315,12 @@ router.get('/templates', adminAuth, requirePermission('email.view'), async (req,
         template_key: template.template_key,
         variables: parseVariables(template),
         translations,
+        // Categorisation + feature-flag link added by migration 098.
+        // Older installs that haven't run the migration yet return
+        // 'core' / null fall-backs so the frontend keeps working
+        // without a hard dependency on the new columns.
+        category: template.category || 'core',
+        feature_flag: template.feature_flag || null,
         updated_at: template.updated_at,
       });
     }
@@ -344,6 +350,9 @@ router.get('/templates/:key', adminAuth, requirePermission('email.view'), async
       template_key: template.template_key,
       variables: parseVariables(template),
       translations,
+      // See list endpoint for the rationale on the || fallbacks.
+      category: template.category || 'core',
+      feature_flag: template.feature_flag || null,
       updated_at: template.updated_at,
     });
   } catch (error) {
diff --git a/frontend/src/services/email.service.ts b/frontend/src/services/email.service.ts
index dc88b47d..a680c96f 100644
--- a/frontend/src/services/email.service.ts
+++ b/frontend/src/services/email.service.ts
@@ -17,11 +17,26 @@ export interface EmailTemplateTranslation {
   body_text?: string;
 }
 
+/**
+ * Categorisation tag added by migration 098. Drives the admin
+ * Templates tab grouping — see EmailConfigPage. Forward-compatible:
+ * unknown values fall back to the 'core' section in the UI.
+ */
+export type EmailTemplateCategory = 'core' | 'customers' | 'billing' | 'quotes' | 'calendar' | string;
+
 export interface EmailTemplate {
   id: number;
   template_key: string;
   variables: string[];
   translations: Record<string, EmailTemplateTranslation>;
+  /** Display group (migration 098). Defaults to 'core' if absent. */
+  category?: EmailTemplateCategory;
+  /**
+   * Name of the feature flag whose `false` state should mark this
+   * template as "Feature off" in the admin UI. `null` = always
+   * active. Migration 098 backfills these.
+   */
+  feature_flag?: string | null;
   updated_at: string;
 }