diff --git a/enterprise/app/controllers/api/v1/accounts/whatsapp_calls_controller.rb b/enterprise/app/controllers/api/v1/accounts/whatsapp_calls_controller.rb
index 28dd378da..a0627ce49 100644
--- a/enterprise/app/controllers/api/v1/accounts/whatsapp_calls_controller.rb
+++ b/enterprise/app/controllers/api/v1/accounts/whatsapp_calls_controller.rb
@@ -106,9 +106,14 @@ class Api::V1::Accounts::WhatsappCallsController < Api::V1::Accounts::BaseContro
 
   def create_outbound_call
     contact_phone = @conversation.contact.phone_number.delete('+')
+    # Claim for the caller only if unassigned at trigger time (before the round-trip); wins over auto-assignment.
+    claim_for_caller = @conversation.assignee_id.nil?
+
     result = provider_service.initiate_call(contact_phone, params[:sdp_offer])
     provider_call_id = result.dig('calls', 0, 'id') || result['call_id']
 
+    @conversation.with_lock { @conversation.update!(assignee: Current.user) } if claim_for_caller
+
     Current.account.calls.create!(
       provider: :whatsapp, inbox: @conversation.inbox, conversation: @conversation, contact: @conversation.contact,
       provider_call_id: provider_call_id, direction: :outgoing, status: 'ringing',
diff --git a/enterprise/app/services/voice/outbound_call_builder.rb b/enterprise/app/services/voice/outbound_call_builder.rb
index 30a74099e..c58407a3f 100644
--- a/enterprise/app/services/voice/outbound_call_builder.rb
+++ b/enterprise/app/services/voice/outbound_call_builder.rb
@@ -17,10 +17,19 @@ class Voice::OutboundCallBuilder
     raise ArgumentError, 'Contact phone number required' if contact.phone_number.blank?
     raise ArgumentError, 'Agent required' if user.blank?
 
+    # Claim for the caller if a reused conversation is unassigned at trigger time; wins over auto-assignment.
+    # New conversations set the assignee at creation instead (see create_conversation!).
+    claim_for_caller = @existing_conversation && @existing_conversation.assignee_id.nil?
+
     ActiveRecord::Base.transaction do
       contact_inbox = ensure_contact_inbox!
       conversation = @existing_conversation || create_conversation!(contact_inbox)
+      # Dial before locking so the Twilio round-trip doesn't hold the conversation row lock.
       call_sid = initiate_call!
+      if claim_for_caller
+        @existing_conversation.lock!
+        @existing_conversation.update!(assignee: user)
+      end
       call = create_call!(conversation, call_sid)
       message = Voice::CallMessageBuilder.new(call).perform!
       call.update!(message_id: message.id)
@@ -44,6 +53,7 @@ class Voice::OutboundCallBuilder
       contact_inbox_id: contact_inbox.id,
       inbox_id: inbox.id,
       contact_id: contact.id,
+      assignee_id: user.id,
       status: :open
     )
   end
diff --git a/spec/enterprise/controllers/api/v1/accounts/whatsapp_calls_controller_spec.rb b/spec/enterprise/controllers/api/v1/accounts/whatsapp_calls_controller_spec.rb
index e0027e273..a66249d5a 100644
--- a/spec/enterprise/controllers/api/v1/accounts/whatsapp_calls_controller_spec.rb
+++ b/spec/enterprise/controllers/api/v1/accounts/whatsapp_calls_controller_spec.rb
@@ -113,6 +113,31 @@ RSpec.describe 'WhatsApp Calls API', type: :request do
       expect(Call.find_by(provider_call_id: 'wacid_outbound')).to have_attributes(direction: 'outgoing', status: 'ringing')
     end
 
+    it 'assigns the conversation to the agent placing the call when it is unassigned' do
+      allow(provider_service).to receive(:initiate_call).and_return({ 'calls' => [{ 'id' => 'wacid_outbound' }] })
+
+      post "/api/v1/accounts/#{account.id}/whatsapp_calls/initiate",
+           params: { conversation_id: initiate_conversation.display_id, sdp_offer: 'sdp_offer' },
+           headers: agent.create_new_auth_token
+
+      expect(response).to have_http_status(:ok)
+      expect(initiate_conversation.reload.assignee_id).to eq(agent.id)
+    end
+
+    it 'keeps the existing assignee when the conversation is already assigned' do
+      other_agent = create(:user, account: account, role: :agent)
+      create(:inbox_member, user: other_agent, inbox: inbox)
+      initiate_conversation.update!(assignee: other_agent)
+      allow(provider_service).to receive(:initiate_call).and_return({ 'calls' => [{ 'id' => 'wacid_outbound' }] })
+
+      post "/api/v1/accounts/#{account.id}/whatsapp_calls/initiate",
+           params: { conversation_id: initiate_conversation.display_id, sdp_offer: 'sdp_offer' },
+           headers: agent.create_new_auth_token
+
+      expect(response).to have_http_status(:ok)
+      expect(initiate_conversation.reload.assignee_id).to eq(other_agent.id)
+    end
+
     it 'sends a permission request and records the wamid when Meta returns NoCallPermission' do
       allow(provider_service).to receive(:initiate_call).and_raise(Voice::CallErrors::NoCallPermission)
       allow(provider_service).to receive(:send_call_permission_request).and_return({ 'messages' => [{ 'id' => 'wamid.req_xyz' }] })
diff --git a/spec/enterprise/services/voice/outbound_call_builder_spec.rb b/spec/enterprise/services/voice/outbound_call_builder_spec.rb
index 796afe715..0dc565eaf 100644
--- a/spec/enterprise/services/voice/outbound_call_builder_spec.rb
+++ b/spec/enterprise/services/voice/outbound_call_builder_spec.rb
@@ -44,6 +44,54 @@ RSpec.describe Voice::OutboundCallBuilder do
       end
     end
 
+    it 'assigns the conversation to the agent placing the call' do
+      call = described_class.perform!(
+        account: account,
+        inbox: inbox,
+        user: user,
+        contact: contact
+      )
+
+      expect(call.conversation.assignee_id).to eq(user.id)
+    end
+
+    it 'keeps the calling agent assigned even when auto-assignment would pick an online agent' do
+      other_agent = create(:user, account: account)
+      create(:inbox_member, inbox: inbox, user: other_agent)
+      create(:inbox_member, inbox: inbox, user: user)
+      inbox.update!(enable_auto_assignment: true)
+      # Only other_agent is online, so round-robin would claim the conversation unless the caller wins at creation.
+      OnlineStatusTracker.update_presence(account.id, 'User', other_agent.id)
+      OnlineStatusTracker.set_status(account.id, other_agent.id, 'online')
+
+      call = described_class.perform!(
+        account: account,
+        inbox: inbox,
+        user: user,
+        contact: contact
+      )
+
+      expect(call.conversation.assignee_id).to eq(user.id)
+    end
+
+    it 'claims a reused conversation for the caller when it is unassigned' do
+      # Reload so the builder gets a DB-fresh record, mirroring the controller's find_by load.
+      conversation = create(:conversation, account: account, inbox: inbox, contact: contact).reload
+
+      described_class.perform!(account: account, inbox: inbox, user: user, contact: contact, conversation: conversation)
+
+      expect(conversation.reload.assignee_id).to eq(user.id)
+    end
+
+    it 'keeps the existing assignee when a reused conversation is already assigned' do
+      other_agent = create(:user, account: account)
+      conversation = create(:conversation, account: account, inbox: inbox, contact: contact, assignee: other_agent).reload
+
+      described_class.perform!(account: account, inbox: inbox, user: user, contact: contact, conversation: conversation)
+
+      expect(conversation.reload.assignee_id).to eq(other_agent.id)
+    end
+
     it 'does not set conversation.identifier or write call state to additional_attributes' do
       call = described_class.perform!(
         account: account,