diff --git a/mediapipe/framework/tool/BUILD b/mediapipe/framework/tool/BUILD
index 56ca0dc65..fbdcf8c9e 100644
--- a/mediapipe/framework/tool/BUILD
+++ b/mediapipe/framework/tool/BUILD
@@ -749,6 +749,7 @@ cc_test(
         ":node_chain_subgraph_cc_proto",
         ":node_chain_subgraph_options_lib",
         ":subgraph_expansion",
+        "//mediapipe/calculators/core:pass_through_calculator",
         "//mediapipe/framework:calculator_cc_proto",
         "//mediapipe/framework:calculator_framework",
         "//mediapipe/framework:graph_service_manager",
diff --git a/mediapipe/framework/tool/subgraph_expansion_test.cc b/mediapipe/framework/tool/subgraph_expansion_test.cc
index b4f58a42e..b6d9950a1 100644
--- a/mediapipe/framework/tool/subgraph_expansion_test.cc
+++ b/mediapipe/framework/tool/subgraph_expansion_test.cc
@@ -37,6 +37,8 @@ namespace mediapipe {
 
 namespace {
 
+using ::testing::HasSubstr;
+
 class SimpleTestCalculator : public CalculatorBase {
  public:
   absl::Status Process(CalculatorContext* cc) override {
@@ -743,5 +745,222 @@ TEST(SubgraphExpansionTest, SimpleSubgraphOptionsTwice) {
   EXPECT_THAT(sky_graph, mediapipe::EqualsProto(expected_graph));
 }
 
+// A subgraph that defines and uses an internal executor with name "xyz".
+class InternalExecutorSubgraph : public Subgraph {
+ public:
+  absl::StatusOr<CalculatorGraphConfig> GetConfig(
+      const SubgraphOptions& options) override {
+    return mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(R"pb(
+      input_stream: "IN:foo"
+      output_stream: "OUT:bar"
+      executor {
+        name: "xyz"
+        type: "ThreadPoolExecutor"
+        options {
+          [mediapipe.ThreadPoolExecutorOptions.ext] { num_threads: 1 }
+        }
+      }
+      node {
+        calculator: "PassThroughCalculator"
+        executor: "xyz"
+        input_stream: "foo"
+        output_stream: "bar"
+      }
+    )pb");
+  }
+};
+REGISTER_MEDIAPIPE_GRAPH(InternalExecutorSubgraph);
+
+// This test confirms that none of existing subgraphs can actually create an
+// executor when used as subgraphs and not like a final graph.
+TEST(SubgraphExpansionTest, SubgraphExecutorIsIgnored) {
+  CalculatorGraphConfig supergraph =
+      mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(R"pb(
+        input_stream: "input"
+        node {
+          calculator: "InternalExecutorSubgraph"
+          input_stream: "IN:input"
+          output_stream: "OUT:output"
+        }
+      )pb");
+  CalculatorGraphConfig expected_graph =
+      mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(R"pb(
+        input_stream: "input"
+        node {
+          name: "internalexecutorsubgraph__PassThroughCalculator"
+          calculator: "PassThroughCalculator"
+          input_stream: "input"
+          output_stream: "output"
+          executor: "xyz"
+        }
+      )pb");
+  MP_EXPECT_OK(tool::ExpandSubgraphs(&supergraph));
+  EXPECT_THAT(supergraph, mediapipe::EqualsProto(expected_graph));
+
+  CalculatorGraph calculator_graph;
+  EXPECT_THAT(calculator_graph.Initialize(supergraph),
+              StatusIs(absl::StatusCode::kInvalidArgument,
+                       HasSubstr("The executor \"xyz\" is "
+                                 "not declared in an ExecutorConfig.")));
+}
+
+class NestedInternalExecutorsSubgraph : public Subgraph {
+ public:
+  absl::StatusOr<CalculatorGraphConfig> GetConfig(
+      const SubgraphOptions& options) override {
+    return mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(R"pb(
+      input_stream: "IN:foo"
+      output_stream: "OUT:bar"
+      node {
+        calculator: "InternalExecutorSubgraph"
+        input_stream: "IN:foo"
+        output_stream: "OUT:bar_0"
+      }
+      executor {
+        name: "xyz"
+        type: "ThreadPoolExecutor"
+        options {
+          [mediapipe.ThreadPoolExecutorOptions.ext] { num_threads: 1 }
+        }
+      }
+      node {
+        calculator: "PassThroughCalculator"
+        executor: "xyz"
+        input_stream: "bar_0"
+        output_stream: "bar_1"
+      }
+      executor {
+        name: "abc"
+        type: "ThreadPoolExecutor"
+        options {
+          [mediapipe.ThreadPoolExecutorOptions.ext] { num_threads: 1 }
+        }
+      }
+      node {
+        calculator: "PassThroughCalculator"
+        executor: "abc"
+        input_stream: "bar_1"
+        output_stream: "bar"
+      }
+    )pb");
+  }
+};
+REGISTER_MEDIAPIPE_GRAPH(NestedInternalExecutorsSubgraph);
+
+TEST(SubgraphExpansionTest, NestedSubgraphExecutorsAreIgnored) {
+  CalculatorGraphConfig supergraph =
+      mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(R"pb(
+        input_stream: "input"
+        node {
+          calculator: "NestedInternalExecutorsSubgraph"
+          input_stream: "IN:input"
+          output_stream: "OUT:output"
+        }
+      )pb");
+  CalculatorGraphConfig expected_graph = mediapipe::ParseTextProtoOrDie<
+      CalculatorGraphConfig>(R"pb(
+    node {
+      name: "nestedinternalexecutorssubgraph__PassThroughCalculator_1"
+      calculator: "PassThroughCalculator"
+      input_stream: "nestedinternalexecutorssubgraph__bar_0"
+      output_stream: "nestedinternalexecutorssubgraph__bar_1"
+      executor: "xyz"
+    }
+    node {
+      name: "nestedinternalexecutorssubgraph__PassThroughCalculator_2"
+      calculator: "PassThroughCalculator"
+      input_stream: "nestedinternalexecutorssubgraph__bar_1"
+      output_stream: "output"
+      executor: "abc"
+    }
+    node {
+      name: "nestedinternalexecutorssubgraph__internalexecutorsubgraph__PassThroughCalculator"
+      calculator: "PassThroughCalculator"
+      input_stream: "input"
+      output_stream: "nestedinternalexecutorssubgraph__bar_0"
+      executor: "xyz"
+    }
+    input_stream: "input"
+  )pb");
+  MP_EXPECT_OK(tool::ExpandSubgraphs(&supergraph));
+  EXPECT_THAT(supergraph, mediapipe::EqualsProto(expected_graph));
+
+  CalculatorGraph calculator_graph;
+  EXPECT_THAT(calculator_graph.Initialize(supergraph),
+              StatusIs(absl::StatusCode::kInvalidArgument,
+                       HasSubstr("The executor \"xyz\" is "
+                                 "not declared in an ExecutorConfig.")));
+}
+
+TEST(SubgraphExpansionTest, GraphExecutorsSubstituteSubgraphExecutors) {
+  CalculatorGraphConfig supergraph =
+      mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(R"pb(
+        input_stream: "input"
+        executor {
+          name: "xyz"
+          type: "ThreadPoolExecutor"
+          options {
+            [mediapipe.ThreadPoolExecutorOptions.ext] { num_threads: 1 }
+          }
+        }
+        executor {
+          name: "abc"
+          type: "ThreadPoolExecutor"
+          options {
+            [mediapipe.ThreadPoolExecutorOptions.ext] { num_threads: 1 }
+          }
+        }
+        node {
+          calculator: "NestedInternalExecutorsSubgraph"
+          input_stream: "IN:input"
+          output_stream: "OUT:output"
+        }
+      )pb");
+  CalculatorGraphConfig expected_graph = mediapipe::ParseTextProtoOrDie<
+      CalculatorGraphConfig>(R"pb(
+    node {
+      name: "nestedinternalexecutorssubgraph__PassThroughCalculator_1"
+      calculator: "PassThroughCalculator"
+      input_stream: "nestedinternalexecutorssubgraph__bar_0"
+      output_stream: "nestedinternalexecutorssubgraph__bar_1"
+      executor: "xyz"
+    }
+    node {
+      name: "nestedinternalexecutorssubgraph__PassThroughCalculator_2"
+      calculator: "PassThroughCalculator"
+      input_stream: "nestedinternalexecutorssubgraph__bar_1"
+      output_stream: "output"
+      executor: "abc"
+    }
+    node {
+      name: "nestedinternalexecutorssubgraph__internalexecutorsubgraph__PassThroughCalculator"
+      calculator: "PassThroughCalculator"
+      input_stream: "input"
+      output_stream: "nestedinternalexecutorssubgraph__bar_0"
+      executor: "xyz"
+    }
+    input_stream: "input"
+    executor {
+      name: "xyz"
+      type: "ThreadPoolExecutor"
+      options {
+        [mediapipe.ThreadPoolExecutorOptions.ext] { num_threads: 1 }
+      }
+    }
+    executor {
+      name: "abc"
+      type: "ThreadPoolExecutor"
+      options {
+        [mediapipe.ThreadPoolExecutorOptions.ext] { num_threads: 1 }
+      }
+    }
+  )pb");
+  MP_EXPECT_OK(tool::ExpandSubgraphs(&supergraph));
+  EXPECT_THAT(supergraph, mediapipe::EqualsProto(expected_graph));
+
+  CalculatorGraph calculator_graph;
+  MP_EXPECT_OK(calculator_graph.Initialize(supergraph));
+}
+
 }  // namespace
 }  // namespace mediapipe