diff --git a/addons/stock/models/stock_quant.py b/addons/stock/models/stock_quant.py
index 15084292a5e..641e3e3f5b4 100644
--- a/addons/stock/models/stock_quant.py
+++ b/addons/stock/models/stock_quant.py
@@ -183,15 +183,17 @@ class StockQuant(models.Model):
                 max_quantity_on_quant = quant.quantity - quant.reserved_quantity
                 if max_quantity_on_quant <= 0:
                     continue
+                max_quantity_on_quant = min(max_quantity_on_quant, quantity)
+                quant.reserved_quantity += max_quantity_on_quant
+                reserved_quants.append((quant, max_quantity_on_quant))
+                quantity -= max_quantity_on_quant
+                available_quantity -= max_quantity_on_quant
             else:
-                max_quantity_on_quant = quant.reserved_quantity
-            max_quantity_on_quant = min(max_quantity_on_quant, quantity)
-
-            quant.reserved_quantity += max_quantity_on_quant
-            reserved_quants.append((quant, max_quantity_on_quant))
-
-            quantity -= max_quantity_on_quant
-            available_quantity -= max_quantity_on_quant
+                max_quantity_on_quant = min(quant.reserved_quantity, abs(quantity))
+                quant.reserved_quantity -= max_quantity_on_quant
+                reserved_quants.append((quant, -max_quantity_on_quant))
+                quantity += max_quantity_on_quant
+                available_quantity += max_quantity_on_quant
 
             if quantity == 0 or available_quantity == 0:
                 break
diff --git a/addons/stock/tests/test_move.py b/addons/stock/tests/test_move.py
index 597945466f4..c08a63a2f8c 100644
--- a/addons/stock/tests/test_move.py
+++ b/addons/stock/tests/test_move.py
@@ -831,6 +831,45 @@ class StockMove(TransactionCase):
         self.assertEqual(quants.reserved_quantity, 0.0)
         self.assertEqual(len(move1.move_line_ids), 0.0)
 
+    def test_unreserve_5(self):
+        """ Check the unreservation of a stock move reserved on multiple quants.
+        """
+        # make some stock
+        self.env['stock.quant']._update_available_quantity(self.product1, self.stock_location, 3)
+        self.env['stock.quant'].create({
+            'product_id': self.product1.id,
+            'location_id': self.stock_location.id,
+            'quantity': 2,
+        })
+        self.assertEqual(len(self.env['stock.quant']._gather(self.product1, self.stock_location)), 2)
+        self.assertEqual(self.env['stock.quant']._get_available_quantity(self.product1, self.stock_location), 5)
+
+        # creation
+        move1 = self.env['stock.move'].create({
+            'name': 'test_unreserve_5',
+            'location_id': self.stock_location.id,
+            'location_dest_id': self.customer_location.id,
+            'product_id': self.product1.id,
+            'product_uom': self.uom_unit.id,
+            'product_uom_qty': 5.0,
+        })
+        self.assertEqual(move1.state, 'draft')
+
+        # confirmation
+        move1.action_confirm()
+        self.assertEqual(move1.state, 'confirmed')
+
+        # assignment
+        move1.action_assign()
+        self.assertEqual(move1.state, 'assigned')
+        self.assertEqual(len(move1.move_line_ids), 1)
+        move1.do_unreserve()
+
+        quants = self.env['stock.quant']._gather(self.product1, self.stock_location)
+        self.assertEqual(len(quants), 2.0)
+        for quant in quants:
+            self.assertEqual(quant.reserved_quantity, 0)
+
     def test_link_assign_1(self):
         """ Test the assignment mechanism when two chained stock moves try to move one unit of an
         untracked product.