diff --git a/compiler/ksp_compiler.py b/compiler/ksp_compiler.py
index 714a1de..00d0795 100644
--- a/compiler/ksp_compiler.py
+++ b/compiler/ksp_compiler.py
@@ -900,6 +900,10 @@ def modifyFunctionDef(self, node, parent_function = None, function_params = None
         node.locals = set()               # a set containing the keys in node.locals_name_subst_dict, but all in lowercase
         node.used = False
 
+        # verify that there are no duplicate argument names in the function definition
+        if len(set(node.parameters)) > 0:
+            raise ksp_ast.ParseException(node, "Function contains duplicate argument names!")
+
         # as we visit the function definition, pass along information to nodes further down the tree of the function parameter names
         params = function_params + node.parameters