diff --git a/addons/sale/models/sale_order_line.py b/addons/sale/models/sale_order_line.py
index f5800e87a53..fbe093a6e43 100644
--- a/addons/sale/models/sale_order_line.py
+++ b/addons/sale/models/sale_order_line.py
@@ -598,10 +598,11 @@ class SaleOrderLine(models.Model):
             'discount': self.discount,
             'price_unit': self.price_unit,
             'tax_ids': [(6, 0, self.tax_id.ids)],
-            'analytic_account_id': self.order_id.analytic_account_id.id,
             'analytic_tag_ids': [(6, 0, self.analytic_tag_ids.ids)],
             'sale_line_ids': [(4, self.id)],
         }
+        if self.order_id.analytic_account_id:
+            res['analytic_account_id'] = self.order_id.analytic_account_id.id
         if optional_values:
             res.update(optional_values)
         if self.display_type:
diff --git a/addons/sale/tests/test_sale_to_invoice.py b/addons/sale/tests/test_sale_to_invoice.py
index 6b4f5b5e809..b493e94cee4 100644
--- a/addons/sale/tests/test_sale_to_invoice.py
+++ b/addons/sale/tests/test_sale_to_invoice.py
@@ -405,3 +405,73 @@ class TestSaleToInvoice(TestSaleCommon):
         })
         downpayment.create_invoices()
         self.assertEqual(so_for_downpayment.invoice_ids[0].company_id.id, so_company_id, "The company of the downpayment invoice should be the same as the one from the SO")
+
+    def test_invoice_analytic_account_default(self):
+        """ Tests whether, when an analytic account rule is set and the so has no analytic account,
+        the default analytic acount is correctly computed in the invoice.
+        """
+        analytic_account_default = self.env['account.analytic.account'].create({'name': 'default'})
+
+        self.env['account.analytic.default'].create({
+            'analytic_id': analytic_account_default.id,
+            'product_id': self.product_a.id,
+        })
+
+        so_form = Form(self.env['sale.order'])
+        so_form.partner_id = self.partner_a
+
+        with so_form.order_line.new() as sol:
+            sol.product_id = self.product_a
+            sol.product_uom_qty = 1
+
+        so = so_form.save()
+        so.action_confirm()
+        so._force_lines_to_invoice_policy_order()
+
+        so_context = {
+            'active_model': 'sale.order',
+            'active_ids': [so.id],
+            'active_id': so.id,
+            'default_journal_id': self.company_data['default_journal_sale'].id,
+        }
+        down_payment = self.env['sale.advance.payment.inv'].with_context(so_context).create({})
+        down_payment.create_invoices()
+
+        aml = self.env['account.move.line'].search([('move_id', 'in', so.invoice_ids.ids)])[0]
+        self.assertRecordValues(aml, [{'analytic_account_id': analytic_account_default.id}])
+
+    def test_invoice_analytic_account_so_not_default(self):
+        """ Tests whether, when an analytic account rule is set and the so has an analytic account,
+        the default analytic acount doesn't replace the one from the so in the invoice.
+        """
+        analytic_account_default = self.env['account.analytic.account'].create({'name': 'default'})
+        analytic_account_so = self.env['account.analytic.account'].create({'name': 'so'})
+
+        self.env['account.analytic.default'].create({
+            'analytic_id': analytic_account_default.id,
+            'product_id': self.product_a.id,
+        })
+
+        so_form = Form(self.env['sale.order'])
+        so_form.partner_id = self.partner_a
+        so_form.analytic_account_id = analytic_account_so
+
+        with so_form.order_line.new() as sol:
+            sol.product_id = self.product_a
+            sol.product_uom_qty = 1
+
+        so = so_form.save()
+        so.action_confirm()
+        so._force_lines_to_invoice_policy_order()
+
+        so_context = {
+            'active_model': 'sale.order',
+            'active_ids': [so.id],
+            'active_id': so.id,
+            'default_journal_id': self.company_data['default_journal_sale'].id,
+        }
+        down_payment = self.env['sale.advance.payment.inv'].with_context(so_context).create({})
+        down_payment.create_invoices()
+
+        aml = self.env['account.move.line'].search([('move_id', 'in', so.invoice_ids.ids)])[0]
+        self.assertRecordValues(aml, [{'analytic_account_id': analytic_account_so.id}])
diff --git a/addons/sale_project/models/sale_order.py b/addons/sale_project/models/sale_order.py
index 9e7e7be805e..83d956403a9 100644
--- a/addons/sale_project/models/sale_order.py
+++ b/addons/sale_project/models/sale_order.py
@@ -357,7 +357,7 @@ class SaleOrderLine(models.Model):
             to this sale order line, or the analytic account of the project which uses this sale order line, if it exists.
         """
         values = super(SaleOrderLine, self)._prepare_invoice_line(**optional_values)
-        if not values['analytic_account_id']:
+        if not values.get('analytic_account_id'):
             if self.task_id.analytic_account_id:
                 values['analytic_account_id'] = self.task_id._get_task_analytic_account_id().id
             elif self.project_id.analytic_account_id: