diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_item_quantity.py b/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_item_quantity.py
index d0949bd331..5ace7af9d4 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_item_quantity.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_item_quantity.py
@@ -48,7 +48,7 @@ def assign_cost_item_quantity(
     If cost item has just 1 quantity and it's IfcQuantityCount, API will
     assume that quantity is used for counting controlled objects
     and it will recalculate the quantity value at the end of the API call
-    as long as the relaedObjects are not IfcConstructionResource which do not
+    as long as the RelatedObjects are not IfcConstructionResource which do not
     count towards the cost item (they only provide value).
 
     :param cost_item: The IfcCostItem to assign parametric quantities to