diff --git a/app/models/invitation_manager.rb b/app/models/invitation_manager.rb
index 53838c50d..60cc0c571 100644
--- a/app/models/invitation_manager.rb
+++ b/app/models/invitation_manager.rb
@@ -62,10 +62,10 @@ def log_event_meeting_invitation_failure(context, member, error)
   end
 
   def chapter_students(chapter)
-    Member.in_group(chapter.groups.students)
+    Member.in_group(chapter.groups.students).distinct
   end
 
   def chapter_coaches(chapter)
-    Member.in_group(chapter.groups.coaches)
+    Member.in_group(chapter.groups.coaches).distinct
   end
 end
diff --git a/spec/models/invitation_manager_deduplication_spec.rb b/spec/models/invitation_manager_deduplication_spec.rb
new file mode 100644
index 000000000..22438b5b6
--- /dev/null
+++ b/spec/models/invitation_manager_deduplication_spec.rb
@@ -0,0 +1,69 @@
+require 'rails_helper'
+
+RSpec.describe InvitationManager do
+  subject(:manager) { InvitationManager.new }
+
+  let(:chapter) { Fabricate(:chapter) }
+  let(:member_in_both_groups) { Fabricate(:member, accepted_toc_at: Time.zone.now) }
+
+  describe '#chapter_students' do
+    context 'when a member has multiple subscriptions to the same group type' do
+      before do
+        students_group1 = Fabricate(:group, name: 'Students', chapter: chapter)
+        students_group2 = Fabricate(:group, name: 'Students', chapter: chapter)
+        students_group1.members << member_in_both_groups
+        students_group2.members << member_in_both_groups
+      end
+
+      it 'returns unique members' do
+        result = manager.send(:chapter_students, chapter)
+
+        expect(result.count).to eq(1)
+        expect(result).to contain_exactly(member_in_both_groups)
+      end
+    end
+  end
+
+  describe '#chapter_coaches' do
+    context 'when a member has multiple subscriptions to the same group type' do
+      before do
+        coaches_group1 = Fabricate(:group, name: 'Coaches', chapter: chapter)
+        coaches_group2 = Fabricate(:group, name: 'Coaches', chapter: chapter)
+        coaches_group1.members << member_in_both_groups
+        coaches_group2.members << member_in_both_groups
+      end
+
+      it 'returns unique members' do
+        result = manager.send(:chapter_coaches, chapter)
+
+        expect(result.count).to eq(1)
+        expect(result).to contain_exactly(member_in_both_groups)
+      end
+    end
+  end
+
+  describe 'sending invitations to members in both students and coaches groups' do
+    let(:workshop) { Fabricate(:workshop, chapter: chapter) }
+    let(:students_group) { Fabricate(:group, name: 'Students', chapter: chapter) }
+    let(:coaches_group) { Fabricate(:group, name: 'Coaches', chapter: chapter) }
+
+    before do
+      students_group.members << member_in_both_groups
+      coaches_group.members << member_in_both_groups
+    end
+
+    it 'sends one invitation per role when audience is everyone' do
+      expect(WorkshopInvitation).to receive(:find_or_create_by)
+        .with(workshop: workshop, member: member_in_both_groups, role: 'Student')
+        .and_call_original
+        .once
+
+      expect(WorkshopInvitation).to receive(:find_or_create_by)
+        .with(workshop: workshop, member: member_in_both_groups, role: 'Coach')
+        .and_call_original
+        .once
+
+      manager.send_workshop_emails(workshop, 'everyone')
+    end
+  end
+end