diff --git a/backend/migrations/core/101_add_customer_gallery_assigned_template.js b/backend/migrations/core/101_add_customer_gallery_assigned_template.js
new file mode 100644
index 00000000..557c400b
--- /dev/null
+++ b/backend/migrations/core/101_add_customer_gallery_assigned_template.js
@@ -0,0 +1,243 @@
+/**
+ * Migration: Add `customer_gallery_assigned` email template.
+ *
+ * Sent when an admin adds new gallery assignments to an existing
+ * customer via the "Manage galleries" dialog on the customer detail
+ * page. Digest-style — one email per save listing every newly added
+ * gallery, not one email per gallery (admins often set up new clients
+ * by adding several galleries in a single sitting).
+ *
+ * Variables:
+ *   - customer_name       greeting name (display name / first name / email local)
+ *   - gallery_count       integer (string) — number of newly added galleries
+ *   - singular            "true" when count === 1 (drives intro wording)
+ *   - multiple            "true" when count >  1
+ *   - gallery_list_html   pre-rendered <ul> with names + dates; passes
+ *                         through unescaped because the service builds it
+ *                         from trusted DB fields (event_name from
+ *                         admin-owned rows + server-rendered dates).
+ *   - gallery_list_text   newline-separated plain-text equivalent for
+ *                         the text/plain body.
+ *   - dashboard_link      URL of /customer/dashboard on the configured
+ *                         frontend origin.
+ *
+ * Category + flag: 'customers' + customerPortal — categorisation
+ * scaffold from migration 098. When the customer portal flag is off,
+ * the Templates admin UI chips this card "Feature off" but it's still
+ * editable.
+ *
+ * Translations: en + de hand-translated; nl/pt/ru/fr machine-generated
+ * and flagged for native review per project convention.
+ *
+ * Idempotent: skips if the template_key already exists.
+ */
+
+const TRANSLATIONS = {
+  en: {
+    subject: 'New gallery access on your account',
+    body_html: `<h2>You have new gallery access</h2>
+<p>Hi {{customer_name}},</p>
+{{#if singular}}<p>Your photographer just gave you access to a new gallery on your account:</p>{{/if}}{{#if multiple}}<p>Your photographer just gave you access to {{gallery_count}} new galleries on your account:</p>{{/if}}
+{{gallery_list_html}}
+<p style="text-align: center; margin: 30px 0;">
+  <a href="{{dashboard_link}}" class="button">Open your dashboard</a>
+</p>
+<p style="font-size: 13px; color: #666;">If the button doesn't work, copy and paste this link into your browser:<br>
+<span style="word-break: break-all;">{{dashboard_link}}</span></p>`,
+    body_text: `You have new gallery access
+
+Hi {{customer_name}},
+
+Your photographer just gave you access to {{gallery_count}} new gallery (or galleries) on your account:
+
+{{gallery_list_text}}
+
+Open your dashboard: {{dashboard_link}}`,
+  },
+  de: {
+    subject: 'Neue Galerie in deinem Konto verfügbar',
+    body_html: `<h2>Du hast Zugriff auf neue Galerien</h2>
+<p>Hallo {{customer_name}},</p>
+{{#if singular}}<p>Dein Fotograf hat dir gerade Zugriff auf eine neue Galerie in deinem Konto gegeben:</p>{{/if}}{{#if multiple}}<p>Dein Fotograf hat dir gerade Zugriff auf {{gallery_count}} neue Galerien in deinem Konto gegeben:</p>{{/if}}
+{{gallery_list_html}}
+<p style="text-align: center; margin: 30px 0;">
+  <a href="{{dashboard_link}}" class="button">Zum Dashboard</a>
+</p>
+<p style="font-size: 13px; color: #666;">Falls der Button nicht funktioniert, kopiere diesen Link in deinen Browser:<br>
+<span style="word-break: break-all;">{{dashboard_link}}</span></p>`,
+    body_text: `Du hast Zugriff auf neue Galerien
+
+Hallo {{customer_name}},
+
+Dein Fotograf hat dir gerade Zugriff auf {{gallery_count}} neue Galerie(n) in deinem Konto gegeben:
+
+{{gallery_list_text}}
+
+Zum Dashboard: {{dashboard_link}}`,
+  },
+  fr: {
+    subject: 'Nouvel accès galerie sur votre compte',
+    body_html: `<h2>Vous avez accès à de nouvelles galeries</h2>
+<p>Bonjour {{customer_name}},</p>
+{{#if singular}}<p>Votre photographe vient de vous donner accès à une nouvelle galerie sur votre compte :</p>{{/if}}{{#if multiple}}<p>Votre photographe vient de vous donner accès à {{gallery_count}} nouvelles galeries sur votre compte :</p>{{/if}}
+{{gallery_list_html}}
+<p style="text-align: center; margin: 30px 0;">
+  <a href="{{dashboard_link}}" class="button">Ouvrir mon tableau de bord</a>
+</p>
+<p style="font-size: 13px; color: #666;">Si le bouton ne fonctionne pas, copiez ce lien dans votre navigateur :<br>
+<span style="word-break: break-all;">{{dashboard_link}}</span></p>`,
+    body_text: `Vous avez accès à de nouvelles galeries
+
+Bonjour {{customer_name}},
+
+Votre photographe vient de vous donner accès à {{gallery_count}} nouvelle(s) galerie(s) sur votre compte :
+
+{{gallery_list_text}}
+
+Tableau de bord : {{dashboard_link}}`,
+  },
+  nl: {
+    subject: 'Nieuwe galerij toegevoegd aan uw account',
+    body_html: `<h2>U heeft toegang tot nieuwe galerijen</h2>
+<p>Hallo {{customer_name}},</p>
+{{#if singular}}<p>Uw fotograaf heeft u zojuist toegang gegeven tot een nieuwe galerij in uw account:</p>{{/if}}{{#if multiple}}<p>Uw fotograaf heeft u zojuist toegang gegeven tot {{gallery_count}} nieuwe galerijen in uw account:</p>{{/if}}
+{{gallery_list_html}}
+<p style="text-align: center; margin: 30px 0;">
+  <a href="{{dashboard_link}}" class="button">Open uw dashboard</a>
+</p>
+<p style="font-size: 13px; color: #666;">Werkt de knop niet? Kopieer dan deze link in uw browser:<br>
+<span style="word-break: break-all;">{{dashboard_link}}</span></p>`,
+    body_text: `U heeft toegang tot nieuwe galerijen
+
+Hallo {{customer_name}},
+
+Uw fotograaf heeft u zojuist toegang gegeven tot {{gallery_count}} nieuwe galerij(en) in uw account:
+
+{{gallery_list_text}}
+
+Dashboard: {{dashboard_link}}`,
+  },
+  pt: {
+    subject: 'Nova galeria disponível em sua conta',
+    body_html: `<h2>Você tem acesso a novas galerias</h2>
+<p>Olá {{customer_name}},</p>
+{{#if singular}}<p>Seu fotógrafo acabou de lhe dar acesso a uma nova galeria em sua conta:</p>{{/if}}{{#if multiple}}<p>Seu fotógrafo acabou de lhe dar acesso a {{gallery_count}} novas galerias em sua conta:</p>{{/if}}
+{{gallery_list_html}}
+<p style="text-align: center; margin: 30px 0;">
+  <a href="{{dashboard_link}}" class="button">Abrir meu painel</a>
+</p>
+<p style="font-size: 13px; color: #666;">Se o botão não funcionar, copie este link no navegador:<br>
+<span style="word-break: break-all;">{{dashboard_link}}</span></p>`,
+    body_text: `Você tem acesso a novas galerias
+
+Olá {{customer_name}},
+
+Seu fotógrafo acabou de lhe dar acesso a {{gallery_count}} nova(s) galeria(s) em sua conta:
+
+{{gallery_list_text}}
+
+Painel: {{dashboard_link}}`,
+  },
+  ru: {
+    subject: 'Новая галерея доступна в вашем аккаунте',
+    body_html: `<h2>У вас новый доступ к галереям</h2>
+<p>Здравствуйте, {{customer_name}}!</p>
+{{#if singular}}<p>Ваш фотограф только что предоставил вам доступ к новой галерее в вашем аккаунте:</p>{{/if}}{{#if multiple}}<p>Ваш фотограф только что предоставил вам доступ к {{gallery_count}} новым галереям в вашем аккаунте:</p>{{/if}}
+{{gallery_list_html}}
+<p style="text-align: center; margin: 30px 0;">
+  <a href="{{dashboard_link}}" class="button">Открыть мой кабинет</a>
+</p>
+<p style="font-size: 13px; color: #666;">Если кнопка не работает, скопируйте эту ссылку в браузер:<br>
+<span style="word-break: break-all;">{{dashboard_link}}</span></p>`,
+    body_text: `У вас новый доступ к галереям
+
+Здравствуйте, {{customer_name}}!
+
+Ваш фотограф только что предоставил вам доступ к {{gallery_count}} новым галереям в вашем аккаунте:
+
+{{gallery_list_text}}
+
+Личный кабинет: {{dashboard_link}}`,
+  },
+};
+
+exports.up = async function(knex) {
+  if (!(await knex.schema.hasTable('email_templates'))) return;
+
+  const existing = await knex('email_templates')
+    .where({ template_key: 'customer_gallery_assigned' })
+    .first();
+  if (existing) {
+    console.log('  customer_gallery_assigned template already exists, skipping insert');
+    return;
+  }
+
+  // Detect schema variant (legacy per-column vs normalized translations).
+  // Newer installs have the email_template_translations table from
+  // migration 075; older ones might still have subject_en/de/... columns
+  // and NOT NULL constraints on the legacy columns. Cover both.
+  const cols = await knex('email_templates').columnInfo();
+  const hasTranslationsTable = await knex.schema.hasTable('email_template_translations');
+
+  const enContent = TRANSLATIONS.en;
+
+  // Build the master row. category/subcategory/feature_flag columns
+  // were added in migration 098 — guard so this migration works on
+  // a slightly older install too.
+  const masterRow = {
+    template_key: 'customer_gallery_assigned',
+    variables: JSON.stringify([
+      'customer_name',
+      'gallery_count',
+      'singular',
+      'multiple',
+      'gallery_list_html',
+      'gallery_list_text',
+      'dashboard_link',
+    ]),
+  };
+  if ('category' in cols)     masterRow.category = 'customers';
+  if ('subcategory' in cols)  masterRow.subcategory = null;
+  if ('feature_flag' in cols) masterRow.feature_flag = 'customerPortal';
+  if ('created_at' in cols)   masterRow.created_at = new Date();
+  if ('updated_at' in cols)   masterRow.updated_at = new Date();
+
+  // Populate any legacy subject_*/body_html_*/body_text_* columns the
+  // schema still carries. Fallback content for non-en locales is the
+  // English string — the translations table below has the real
+  // per-locale copy. This only matters if the install hasn't run
+  // migration 075 yet, which is rare but possible.
+  for (const colName of Object.keys(cols)) {
+    if (colName === 'subject' || /^subject_[a-z]{2,3}$/i.test(colName)) {
+      masterRow[colName] = enContent.subject;
+    } else if (colName === 'body_html' || /^body_html_[a-z]{2,3}$/i.test(colName)) {
+      masterRow[colName] = enContent.body_html;
+    } else if (colName === 'body_text' || /^body_text_[a-z]{2,3}$/i.test(colName)) {
+      masterRow[colName] = enContent.body_text;
+    }
+  }
+
+  const inserted = await knex('email_templates').insert(masterRow).returning('id');
+  const templateId = typeof inserted[0] === 'object' ? inserted[0].id : inserted[0];
+
+  if (hasTranslationsTable && templateId) {
+    for (const [language, content] of Object.entries(TRANSLATIONS)) {
+      await knex('email_template_translations').insert({
+        template_id: templateId,
+        language,
+        subject: content.subject,
+        body_html: content.body_html,
+        body_text: content.body_text,
+        created_at: new Date(),
+        updated_at: new Date(),
+      });
+    }
+  }
+
+  console.log('  customer_gallery_assigned template inserted with 6 translations');
+};
+
+exports.down = async function(knex) {
+  if (!(await knex.schema.hasTable('email_templates'))) return;
+  await knex('email_templates').where({ template_key: 'customer_gallery_assigned' }).del();
+};
diff --git a/backend/src/services/customerAccountsService.js b/backend/src/services/customerAccountsService.js
index 9511d303..96255c6d 100644
--- a/backend/src/services/customerAccountsService.js
+++ b/backend/src/services/customerAccountsService.js
@@ -671,6 +671,11 @@ async function setAssignmentsForCustomer(customerId, targetEventIds, adminId, tr
       .del();
   }
 
+  // Collect the event IDs that actually landed in the DB (i.e. survived
+  // the archived/missing filter) so the post-commit notifier knows
+  // exactly which galleries to mention in the email. Empty by default.
+  let addedEventIds = [];
+
   if (toAdd.length > 0) {
     // Validate the events exist + are not archived before inserting.
     // Mirrors the customer-side check in setAssignmentsForEvent so an
@@ -695,10 +700,121 @@ async function setAssignmentsForCustomer(customerId, targetEventIds, adminId, tr
     }));
     if (rows.length > 0) {
       await trx('event_customer_assignments').insert(rows);
+      addedEventIds = rows.map((r) => r.event_id);
     }
   }
 
-  return { added: toAdd.length, removed: toRemove.length };
+  // Notify the customer about newly-accessible galleries. Best-effort
+  // — a failure here must not roll back the assignment write, so we
+  // fire-and-forget after the transactional work is done and swallow
+  // any throw with a warn log. Skipped when no new rows were added.
+  if (addedEventIds.length > 0) {
+    notifyCustomerOfNewAssignments(customerId, addedEventIds).catch((err) => {
+      logger.warn('Failed to queue customer_gallery_assigned email', {
+        customerId, addedEventIds, error: err?.message,
+      });
+    });
+  }
+
+  return { added: toAdd.length, removed: toRemove.length, addedEventIds };
+}
+
+/**
+ * Queue a `customer_gallery_assigned` email summarising newly-granted
+ * gallery access for one customer. Called by setAssignmentsForCustomer
+ * after the transaction commits.
+ *
+ * Rules:
+ *   - One email per save (digest), not one per gallery.
+ *   - Archived + expired events are filtered out — the customer would
+ *     hit a "this gallery has expired" notice anyway, so naming them
+ *     in the email just confuses people.
+ *   - Deactivated customers (is_active=false) get no email — their
+ *     login is off, so a "you have new access" message would be
+ *     misleading.
+ *   - Customers without an email on file are skipped (silently —
+ *     should never happen for accepted accounts but defensive).
+ *   - Email failures are logged but never bubble up; the caller's
+ *     `.catch` handler logs again at a more specific call site.
+ */
+async function notifyCustomerOfNewAssignments(customerId, addedEventIds) {
+  if (!addedEventIds || addedEventIds.length === 0) return;
+
+  const customer = await db('customer_accounts')
+    .where({ id: customerId, is_active: formatBoolean(true) })
+    .select('id', 'email', 'display_name', 'first_name', 'preferred_language')
+    .first();
+  if (!customer || !customer.email) {
+    logger.info('Skip customer_gallery_assigned email: customer missing/inactive/no email', {
+      customerId,
+    });
+    return;
+  }
+
+  // Filter the added events to those the customer can actually open.
+  // Archived events are hard-skipped; expired ones (expires_at in the
+  // past) would render as "Expired DD MMM" in the dashboard and lead
+  // to a confusing "I clicked the link in the email and got a 410"
+  // experience — drop those too.
+  const now = new Date();
+  const events = await db('events')
+    .whereIn('id', addedEventIds)
+    .where('is_archived', formatBoolean(false))
+    .andWhere(function() {
+      this.whereNull('expires_at').orWhere('expires_at', '>', now);
+    })
+    .orderBy('event_date', 'desc')
+    .select('id', 'slug', 'event_name', 'event_date');
+
+  if (events.length === 0) {
+    logger.info('Skip customer_gallery_assigned email: all added events archived/expired', {
+      customerId, addedEventIds,
+    });
+    return;
+  }
+
+  // Build the gallery list block. HTML is whitelisted via
+  // HTML_PASSTHROUGH_KEYS in emailProcessor so the <ul> survives the
+  // body-html escaping pass. Names + dates come from admin-controlled
+  // DB rows; the date is server-rendered.
+  const { formatDate } = require('../utils/dateFormatter');
+  const { escapeHtml } = require('../utils/formatters');
+  const language = customer.preferred_language || 'en';
+
+  const formattedRows = await Promise.all(events.map(async (ev) => ({
+    name: ev.event_name || ev.slug,
+    date: ev.event_date ? await formatDate(ev.event_date, language) : '',
+  })));
+
+  const galleryListHtml = `<ul>\n${
+    formattedRows.map((r) => {
+      const safeName = escapeHtml(r.name);
+      const safeDate = r.date ? ` — ${escapeHtml(r.date)}` : '';
+      return `  <li>${safeName}${safeDate}</li>`;
+    }).join('\n')
+  }\n</ul>`;
+
+  const galleryListText = formattedRows
+    .map((r) => r.date ? `- ${r.name} (${r.date})` : `- ${r.name}`)
+    .join('\n');
+
+  const frontendUrl = (await getFrontendBaseUrl()) || 'http://localhost:3000';
+  const customerName = customer.display_name?.trim()
+    || customer.first_name?.trim()
+    || (customer.email ? customer.email.split('@')[0] : '');
+
+  await queueEmail(null, customer.email, 'customer_gallery_assigned', {
+    customer_name: customerName,
+    gallery_count: String(events.length),
+    // `singular` / `multiple` drive the {{#if}} blocks in the
+    // template — safeTemplateReplace treats anything non-empty +
+    // non-false as truthy, so passing literal 'true' / '' works.
+    singular: events.length === 1 ? 'true' : '',
+    multiple: events.length > 1 ? 'true' : '',
+    gallery_list_html: galleryListHtml,
+    gallery_list_text: galleryListText,
+    dashboard_link: `${frontendUrl}/customer/dashboard`,
+  });
 }
 
 /**
diff --git a/backend/src/services/emailProcessor.js b/backend/src/services/emailProcessor.js
index 5e07f517..ecab43cb 100644
--- a/backend/src/services/emailProcessor.js
+++ b/backend/src/services/emailProcessor.js
@@ -388,9 +388,14 @@ function htmlToText(html) {
 // else (event_name, host_name, customer_name, …) is admin-supplied free
 // text and gets escaped to prevent stored-HTML injection in customer mail.
 const HTML_PASSTHROUGH_KEYS = new Set([
-  'welcome_message', // already HTML (formatWelcomeMessage escapes + nl2br)
-  'gallery_link',    // server-generated URL (adminEvents.js)
-  'client_link',     // server-generated URL (adminEvents.js)
+  'welcome_message',     // already HTML (formatWelcomeMessage escapes + nl2br)
+  'gallery_link',        // server-generated URL (adminEvents.js)
+  'client_link',         // server-generated URL (adminEvents.js)
+  // customer_gallery_assigned template (#354 follow-up): server-rendered
+  // <ul> of newly-added galleries. Built in customerAccountsService from
+  // trusted DB rows (event_name comes from admin-owned events; the date
+  // is server-rendered) — escaping it here would double-escape the markup.
+  'gallery_list_html',
 ]);
 
 const { escapeHtml } = require('../utils/formatters');