diff --git a/onnxruntime/core/graph/graph.cc b/onnxruntime/core/graph/graph.cc
index 4b355501a4..321c48025b 100644
--- a/onnxruntime/core/graph/graph.cc
+++ b/onnxruntime/core/graph/graph.cc
@@ -1494,6 +1494,25 @@ Status Graph::BuildConnections(std::unordered_set<std::string>& outer_scope_node
                 ORT_IGNORE_RETURN_VALUE(outer_scope_node_args_consumed.insert(input_arg_name));
               }
             }
+          } else {
+            // Check all the inputs are found.
+            //
+            // Ignore a Fused node as it could have moved things like initializers to a different device
+            // (they're internally available to the fused node but removed from the Graph instance).
+            // Fusion happens after the model was loaded in full so we know the inputs were valid originally.
+            bool check = node.NodeType() != Node::Type::Fused;
+#if defined(ENABLE_TRAINING)
+            // Only check initial model load for training as graph modifications there also render inputs 'invalid'.
+            check = check && num_resolves_ == 0;
+#endif
+            if (check &&
+                resolve_context_.inputs_and_initializers.find(input_arg_name) ==
+                    resolve_context_.inputs_and_initializers.cend() &&
+                // if we're manually creating a Graph for use as a subgraph the outer scope names are manually set
+                outer_scope_node_arg_names_.find(input_arg_name) == outer_scope_node_arg_names_.cend()) {
+              return ORT_MAKE_STATUS(ONNXRUNTIME, INVALID_ARGUMENT, "Invalid model. Node input '", input_arg_name,
+                                     "' is not a graph input, initializer, or output of a previous node.");
+            }
           }
         }
       }
@@ -2396,7 +2415,7 @@ void Graph::InitFunctionBodyForNode(Node& node) {
     }
 
     auto func_ptr = std::make_unique<onnxruntime::FunctionImpl>(*this, node.Index(), onnx_function_proto,
-                                                                        logger_);
+                                                                logger_);
 
     function_container_.emplace_back(std::move(func_ptr));
     node.SetFunctionBody(*function_container_.back());
diff --git a/onnxruntime/test/ir/graph_test.cc b/onnxruntime/test/ir/graph_test.cc
index 6ea5688c9d..a29f4adb95 100644
--- a/onnxruntime/test/ir/graph_test.cc
+++ b/onnxruntime/test/ir/graph_test.cc
@@ -446,8 +446,8 @@ TEST_F(GraphTest, LocalCustomRegistry) {
 }
 
 // Tests the case where function op and function body ops belong to different domains.
-// Tests that such a model can be loaded successfully, function body initialization is 
-// successful and domain and verison mapping for each node is successful (by verifying 
+// Tests that such a model can be loaded successfully, function body initialization is
+// successful and domain and verison mapping for each node is successful (by verifying
 // op schema for each of the function body nodes can be found).
 TEST_F(GraphTest, FunctionOpsetImportTest) {
   std::shared_ptr<Model> model;
@@ -1880,5 +1880,33 @@ TEST_F(GraphTest, SetInputsAndSetOutputs_NewInputAndOutput) {
   ASSERT_TRUE(std::find(outputs.begin(), outputs.end(), sum_with_z) != outputs.end())
       << "expected new output sum_with_z";
 }
+
+TEST_F(GraphTest, LoadModelMissingInput) {
+  ModelProto m;
+  m.set_ir_version(ONNX_NAMESPACE::IR_VERSION);
+  ImportOpset(m, "", 13);
+  GraphProto& g = *m.mutable_graph();
+  NodeProto* node = g.add_node();
+  *node->add_input() = "x";
+  *node->add_input() = "y";
+  *node->add_output() = "z";
+  node->set_op_type("Reshape");
+  node->set_domain("");
+
+  // add 'x' as a graph input but not 'y'
+  ValueInfoProto* input1 = g.add_input();
+  input1->set_name("x");
+  SetTypeAndShape(input1->mutable_type()->mutable_tensor_type(), 1, {4});
+  ValueInfoProto* output = g.add_output();
+  output->set_name("z");
+  SetTypeAndShape(output->mutable_type()->mutable_tensor_type(), 1, {2, 2});
+
+  std::shared_ptr<Model> model;
+  Status st = Model::Load(std::move(m), model, nullptr, *logger_);
+  ASSERT_FALSE(st.IsOK());
+  ASSERT_THAT(st.ErrorMessage(), testing::HasSubstr("Invalid model. Node input 'y' is not a graph input, "
+                                                    "initializer, or output of a previous node."));
+}
+
 }  // namespace test
 }  // namespace onnxruntime