diff --git a/addons/payment_custom/models/payment_transaction.py b/addons/payment_custom/models/payment_transaction.py
index dcb81ec4f90..9395bcd64d1 100644
--- a/addons/payment_custom/models/payment_transaction.py
+++ b/addons/payment_custom/models/payment_transaction.py
@@ -31,6 +31,24 @@ class PaymentTransaction(models.Model):
             'reference': self.reference,
         }
 
+    def _get_communication(self):
+        """ Return the communication the user should use for their transaction.
+
+        This communication might change according to the settings and the accounting localization.
+
+        Note: self.ensure_one()
+
+        :return: The selected communication.
+        :rtype: str
+        """
+        self.ensure_one()
+        communication = ""
+        if hasattr(self, 'invoice_ids') and self.invoice_ids:
+            communication = self.invoice_ids[0].payment_reference
+        elif hasattr(self, 'sale_order_ids') and self.sale_order_ids:
+            communication = self.sale_order_ids[0].reference
+        return communication or self.reference
+
     def _get_tx_from_notification_data(self, provider_code, notification_data):
         """ Override of payment to find the transaction based on custom data.
 
diff --git a/addons/payment_custom/tests/__init__.py b/addons/payment_custom/tests/__init__.py
new file mode 100644
index 00000000000..a7483b2cbcc
--- /dev/null
+++ b/addons/payment_custom/tests/__init__.py
@@ -0,0 +1,3 @@
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from . import test_payment_transaction
diff --git a/addons/payment_custom/tests/test_payment_transaction.py b/addons/payment_custom/tests/test_payment_transaction.py
new file mode 100644
index 00000000000..10e0a4844d3
--- /dev/null
+++ b/addons/payment_custom/tests/test_payment_transaction.py
@@ -0,0 +1,61 @@
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import Command, fields
+from odoo.tests import tagged
+
+from odoo.addons.payment.tests.common import PaymentCommon
+
+
+@tagged('-at_install', 'post_install')
+class TestPaymentTransaction(PaymentCommon):
+
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+
+        cls.provider = cls._prepare_provider(code='custom')
+        cls.product = cls.env['product.product'].create({
+            'name': "test product", 'list_price': cls.amount
+        })
+
+    def test_communication_based_on_transaction_reference(self):
+        """ Test that the payment communication falls back to the transaction reference when there
+        is no linked invoice or sales order. """
+        tx = self._create_transaction(flow='direct', reference="test")
+
+        self.assertEqual(tx._get_communication(), "test")
+
+    def test_communication_for_invoice(self):
+        """ Test that the communication displayed is the invoice payment reference. """
+        account_payment_module = self.env['ir.module.module']._get('account_payment')
+        if account_payment_module.state != 'installed':
+            self.skipTest("account_payment module is not installed")
+
+        invoice = self.env['account.move'].create({
+            'move_type': 'in_invoice',
+            'partner_id': self.partner.id,
+            'invoice_date': fields.Date.from_string('2019-01-01'),
+            'currency_id': self.currency.id,
+            'invoice_line_ids': [Command.create({'product_id': self.product.id, 'quantity': 1})],
+        })
+        invoice.action_post()
+        tx = self._create_transaction(flow='direct', invoice_ids=[invoice.id])
+
+        invoice.payment_reference = "test"
+        self.assertEqual(tx._get_communication(), "test")
+
+    def test_communication_for_sale_order(self):
+        """ Test that the communication displayed is the sale order reference. """
+        sale_module = self.env['ir.module.module']._get('sale')
+        if sale_module.state != 'installed':
+            self.skipTest("sale module is not installed")
+
+        sale_order = self.env['sale.order'].create({
+            'partner_id': self.partner.id,
+            'order_line': [Command.create({'product_id': self.product.id, 'product_uom_qty': 1})],
+        })
+        sale_order.action_confirm()
+        tx = self._create_transaction(flow='direct', sale_order_ids=[sale_order.id])
+
+        sale_order.reference = "test"
+        self.assertEqual(tx._get_communication(), "test")
diff --git a/addons/payment_custom/views/payment_custom_templates.xml b/addons/payment_custom/views/payment_custom_templates.xml
index d43759de4f8..3cd980fbc17 100644
--- a/addons/payment_custom/views/payment_custom_templates.xml
+++ b/addons/payment_custom/views/payment_custom_templates.xml
@@ -34,7 +34,7 @@
 
         <xpath expr="//div[@name='o_payment_status_alert']" position="inside">
             <t t-set="qr_code"
-               t-value="tx.provider_id.sudo().qr_code and tx.company_id.sudo().partner_id.bank_ids[:1].build_qr_code_base64(tx.amount, tx.reference, None, tx.currency_id, tx.partner_id)"
+               t-value="tx.provider_id.sudo().qr_code and tx.company_id.sudo().partner_id.bank_ids[:1].build_qr_code_base64(tx.amount, tx._get_communication(), None, tx.currency_id, tx.partner_id)"
             />
             <t t-if="tx.provider_id.sudo().code == 'custom' and qr_code">
                 <div class="position-relative order-2 d-flex flex-md-column justify-content-center align-items-center align-items-md-stretch w-100 w-md-auto">
@@ -74,11 +74,12 @@
                 <div class="card flex-grow-1">
                     <div class="card-body">
                         <t>$0</t>
-                        <t t-if="tx.reference">
+                        <t t-if="tx._get_communication()">
                             <hr class="w-100"/>
                             <strong class="mt-auto">Communication: </strong>
-                            <span t-out="tx.reference"/>
+                            <span t-out="tx._get_communication()"/>
                         </t>
+                        <t t-if="tx.reference"/>  <!-- Remove in master -->
                     </div>
                 </div>
             </div>