diff --git a/InvenTree/stock/api.py b/InvenTree/stock/api.py
index 77b35f45d0..450f6e95f1 100644
--- a/InvenTree/stock/api.py
+++ b/InvenTree/stock/api.py
@@ -12,6 +12,7 @@ from django.db.models import Q
 from .models import StockLocation, StockItem
 from .models import StockItemTracking
 
+from order.models import SalesOrder
 from part.models import Part, PartCategory
 
 from .serializers import StockItemSerializer
@@ -387,7 +388,7 @@ class StockList(generics.ListCreateAPIView):
                     stock_list = stock_list.filter(part=part_id)
 
             except (ValueError, Part.DoesNotExist):
-                pass
+                raise ValidationError({"part": "Invalid Part ID specified"})
 
         # Does the client wish to filter by the 'ancestor'?
         anc_id = self.request.query_params.get('ancestor', None)
@@ -400,7 +401,7 @@ class StockList(generics.ListCreateAPIView):
                 stock_list = stock_list.filter(id__in=[item.pk for item in ancestor.children.all()])
 
             except (ValueError, Part.DoesNotExist):
-                pass
+                raise ValidationError({"ancestor": "Invalid ancestor ID specified"})
 
         # Does the client wish to filter by stock location?
         loc_id = self.request.query_params.get('location', None)
@@ -433,7 +434,7 @@ class StockList(generics.ListCreateAPIView):
                 stock_list = stock_list.filter(part__category__in=category.getUniqueChildren())
 
             except (ValueError, PartCategory.DoesNotExist):
-                pass
+                raise ValidationError({"category": "Invalid category id specified"})
 
         # Filter by StockItem status
         status = self.request.query_params.get('status', None)
@@ -465,10 +466,22 @@ class StockList(generics.ListCreateAPIView):
         if manufacturer is not None:
             stock_list = stock_list.filter(supplier_part__manufacturer=manufacturer)
 
+        # Filter by sales order
+        sales_order = self.request.query_params.get('sales_order', None)
+
+        if sales_order is not None:
+            try:
+                sales_order = SalesOrder.objects.get(pk=sales_order)
+                lines = [line.pk for line in sales_order.lines.all()]
+                stock_list = stock_list.filter(sales_order_line__in=lines)
+            except (SalesOrder.DoesNotExist, ValueError):
+                raise ValidationError({'sales_order': 'Invalid SalesOrder object specified'})
+
         # Also ensure that we pre-fecth all the related items
         stock_list = stock_list.prefetch_related(
             'part',
             'part__category',
+            'sales_order_line__order',
             'location'
         )
 
@@ -493,6 +506,7 @@ class StockList(generics.ListCreateAPIView):
         'customer',
         'belongs_to',
         'build',
+        'sales_order_line'
     ]
 
 
diff --git a/InvenTree/stock/migrations/0028_auto_20200421_0724.py b/InvenTree/stock/migrations/0028_auto_20200421_0724.py
new file mode 100644
index 0000000000..61ebe97039
--- /dev/null
+++ b/InvenTree/stock/migrations/0028_auto_20200421_0724.py
@@ -0,0 +1,18 @@
+# Generated by Django 3.0.5 on 2020-04-21 07:24
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0027_stockitem_sales_order'),
+    ]
+
+    operations = [
+        migrations.RenameField(
+            model_name='stockitem',
+            old_name='sales_order',
+            new_name='sales_order_line',
+        ),
+    ]
diff --git a/InvenTree/stock/models.py b/InvenTree/stock/models.py
index 1129a3ce79..4970083f0c 100644
--- a/InvenTree/stock/models.py
+++ b/InvenTree/stock/models.py
@@ -266,13 +266,13 @@ class StockItem(MPTTModel):
         try:
             # If this StockItem is assigned to a SalesOrderLineItem,
             # the "Part" that the line item references is the same as the part that THIS references
-            if self.sales_order is not None:
+            if self.sales_order_line is not None:
 
-                if self.sales_order.part == None:
-                    raise ValidationError({'sales_order': _('Stock item cannot be assigned to a LineItem which does not reference a part')})
+                if self.sales_order_line.part == None:
+                    raise ValidationError({'sales_order_line': _('Stock item cannot be assigned to a LineItem which does not reference a part')})
                 
-                if not self.sales_order.part == self.part:
-                    raise ValidationError({'sales_order': _('Stock item does not reference the same part object as the LineItem')})
+                if not self.sales_order_line.part == self.part:
+                    raise ValidationError({'sales_order_line': _('Stock item does not reference the same part object as the LineItem')})
 
         except SalesOrderLineItem.DoesNotExist:
             pass
@@ -369,7 +369,7 @@ class StockItem(MPTTModel):
         help_text=_('Purchase order for this stock item')
     )
 
-    sales_order = models.ForeignKey(
+    sales_order_line = models.ForeignKey(
         SalesOrderLineItem,
         on_delete=models.SET_NULL,
         related_name='stock_items',