diff --git a/app/assets/javascripts/add-all-chapters.js b/app/assets/javascripts/add-all-chapters.js
new file mode 100644
index 000000000..daaa2759a
--- /dev/null
+++ b/app/assets/javascripts/add-all-chapters.js
@@ -0,0 +1,23 @@
+// "Add to all" option at the top of the chapters dropdown on the admin event
+// form. Selects every chapter so organisers don't have to pick each one.
+// Chosen only renders <option>s, so the row is injected into its dropdown.
+
+/* global $ */
+
+$(() => {
+  const $chapters = $("#event_chapter_ids");
+
+  $chapters.on("chosen:ready", () => {
+    const $addAll = $('<div class="add-all-chapters">Add to all</div>');
+    $chapters.next(".chosen-container").find(".chosen-drop").prepend($addAll);
+
+    // mousedown fires before Chosen's blur handling closes the dropdown;
+    // stopPropagation keeps Chosen's container handler from reopening it
+    $addAll.on("mousedown", (event) => {
+      event.preventDefault();
+      event.stopPropagation();
+      $chapters.find("option").prop("selected", true);
+      $chapters.trigger("change").trigger("chosen:updated").trigger("chosen:close");
+    });
+  });
+});
diff --git a/app/assets/javascripts/application.js b/app/assets/javascripts/application.js
index 669d5a754..c45a61a0a 100644
--- a/app/assets/javascripts/application.js
+++ b/app/assets/javascripts/application.js
@@ -21,6 +21,7 @@
 //= require pickadate/picker.date
 //= require pickadate/picker.time
 //= require subscriptions-toggle
+//= require add-all-chapters
 //= require invitations
 //= require dietary-restrictions
 //= require cocoon
diff --git a/app/assets/stylesheets/main.scss b/app/assets/stylesheets/main.scss
index 754c03671..0ddae0306 100644
--- a/app/assets/stylesheets/main.scss
+++ b/app/assets/stylesheets/main.scss
@@ -26,6 +26,16 @@ form .hint {
   margin-bottom: 1.14286rem;
 }
 
+.add-all-chapters {
+  cursor: pointer;
+  font-weight: bold;
+  padding: 8px 6px 4px;
+}
+
+.add-all-chapters:hover {
+  color: #1e90ff;
+}
+
 .small-image {
   max-height: 100px;
 }
diff --git a/spec/features/admin/manage_event_spec.rb b/spec/features/admin/manage_event_spec.rb
index 93fcde90e..443b702b6 100644
--- a/spec/features/admin/manage_event_spec.rb
+++ b/spec/features/admin/manage_event_spec.rb
@@ -11,10 +11,24 @@
   scenario 'accessing an event' do
     visit admin_event_path(event)
 
-    expect(page).to have_content(event.name)
+    expect(page).to have_text(event.name)
 
-    expect(page).to have_content 'Venue'
-    expect(page).to have_content event.venue.name
+    expect(page).to have_text 'Venue'
+    expect(page).to have_text event.venue.name
+  end
+
+  scenario 'adding all chapters to an event with one click', :js do
+    Fabricate.times(2, :chapter)
+    visit edit_admin_event_path(event)
+
+    find('#event_chapter_ids_chosen').click
+    find('.add-all-chapters', text: 'Add to all').click
+    expect(page).to have_no_css('#event_chapter_ids_chosen.chosen-with-drop')
+
+    click_on 'Save'
+
+    expect(page).to have_text('You have just updated the event')
+    expect(event.reload.chapter_ids).to match_array(Chapter.ids)
   end
 
   scenario 'verifying an attendance' do
@@ -23,7 +37,7 @@
 
     click_on 'Verify'
 
-    expect(page).to have_content "You have verified #{invitation.member.full_name}'s spot at the event!"
+    expect(page).to have_text "You have verified #{invitation.member.full_name}'s spot at the event!"
     expect(invitation.reload.verified_by).to eq(member)
   end
 
@@ -33,8 +47,8 @@
 
     click_on 'Cancel'
 
-    expect(page).to have_content "You have cancelled #{invitation.member.full_name}'s attendance."
-    expect(invitation.reload.attending).to eq(false)
+    expect(page).to have_text "You have cancelled #{invitation.member.full_name}'s attendance."
+    expect(invitation.reload.attending).to be(false)
   end
 
   scenario 'accessing a list of attendee emails' do
@@ -44,9 +58,9 @@
 
     click_on 'Emails'
 
-    expect(page).to have_content('COACHES')
-    expect(page).to have_content(coach_invitation.member.email)
-    expect(page).to have_content('STUDENTS')
-    expect(page).to have_content(student_invitation.member.email)
+    expect(page).to have_text('COACHES')
+    expect(page).to have_text(coach_invitation.member.email)
+    expect(page).to have_text('STUDENTS')
+    expect(page).to have_text(student_invitation.member.email)
   end
 end