diff --git a/extension/flat_tensor/test/flat_tensor_data_map_test.cpp b/extension/flat_tensor/test/flat_tensor_data_map_test.cpp
index 5a94b47b954..37e1cd2edac 100644
--- a/extension/flat_tensor/test/flat_tensor_data_map_test.cpp
+++ b/extension/flat_tensor/test/flat_tensor_data_map_test.cpp
@@ -33,8 +33,8 @@ class FlatTensorDataMapTest : public ::testing::Test {
     // first.
     executorch::runtime::runtime_init();
 
-    // Load data map. The eager linear model is defined at:
-    // //executorch/test/models/linear_model.py
+    // Load data map. The eager addmul model is defined at:
+    // //executorch/test/models/export_program.py
     const char* path = std::getenv("ET_MODULE_ADD_MUL_DATA_PATH");
     Result<FileDataLoader> loader = FileDataLoader::from(path);
     ASSERT_EQ(loader.error(), Error::Ok);
diff --git a/runtime/executor/merged_data_map.h b/runtime/executor/merged_data_map.h
new file mode 100644
index 00000000000..0f0175098ae
--- /dev/null
+++ b/runtime/executor/merged_data_map.h
@@ -0,0 +1,149 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <executorch/runtime/core/named_data_map.h>
+
+namespace executorch {
+namespace ET_RUNTIME_NAMESPACE {
+namespace internal {
+
+/**
+ * A NamedDataMap implementation that wraps other NamedDataMaps.
+ */
+class MergedDataMap final : public NamedDataMap {
+ public:
+  /**
+   * Creates a new NamedDataMap that wraps two other data maps.
+   *
+   * @param[in] first The first NamedDataMap to merge.
+   * @param[in] second The second NamedDataMap to merge.
+   * Note: the data maps must outlive the MergedDataMap instance.
+   */
+  static Result<MergedDataMap> load(
+      const NamedDataMap* first,
+      const NamedDataMap* second) {
+    ET_CHECK_OR_RETURN_ERROR(
+        first != nullptr && second != nullptr,
+        InvalidArgument,
+        "Input data map is null.");
+
+    // Check for duplicate keys.
+    for (uint32_t k = 0; k < first->get_num_keys().get(); k++) {
+      const auto key = first->get_key(k).get();
+      ET_CHECK_OR_RETURN_ERROR(
+          second->get_tensor_layout(key).error() == Error::NotFound,
+          InvalidArgument,
+          "Duplicate key %s.",
+          key);
+    }
+    return MergedDataMap(first, second);
+  }
+
+  /**
+   * Retrieve the tensor_layout for the specified key.
+   *
+   * @param[in] key The name of the tensor to get metadata on.
+   *
+   * @return Error::NotFound if the key is not present.
+   */
+  ET_NODISCARD
+  Result<const TensorLayout> get_tensor_layout(
+      executorch::aten::string_view key) const override {
+    auto layout = first_->get_tensor_layout(key);
+    if (layout.ok()) {
+      return layout.get();
+    }
+    if (layout.error() != Error::NotFound) {
+      return layout.error();
+    }
+    return second_->get_tensor_layout(key);
+  }
+
+  /**
+   * Retrieve read-only data for the specified key.
+   *
+   * @param[in] key The name of the tensor to get data on.
+   *
+   * @return error if the key is not present or data cannot be loaded.
+   */
+  ET_NODISCARD
+  Result<FreeableBuffer> get_data(
+      executorch::aten::string_view key) const override {
+    auto data = first_->get_data(key);
+    if (data.error() != Error::NotFound) {
+      return data;
+    }
+    return second_->get_data(key);
+  }
+
+  /**
+   * Loads the data of the specified tensor into the provided buffer.
+   * Not used in the MergedDataMap.
+   *
+   * @param[in] key The name of the tensor to get the data of.
+   * @param[in] buffer The buffer to load data into. Must point to at least
+   * `size` bytes of memory.
+   * @param[in] size The number of bytes to load.
+   *
+   * @returns an Error indicating if the load was successful.
+   */
+  ET_NODISCARD Error load_data_into(
+      ET_UNUSED executorch::aten::string_view key,
+      ET_UNUSED void* buffer,
+      ET_UNUSED size_t size) const override {
+    return Error::NotImplemented;
+  }
+
+  /**
+   * @returns The number of keys in the map.
+   */
+  ET_NODISCARD Result<uint32_t> get_num_keys() const override {
+    return first_->get_num_keys().get() + second_->get_num_keys().get();
+  }
+
+  /**
+   * @returns The key at the specified index, error if index out of bounds.
+   */
+  ET_NODISCARD Result<const char*> get_key(uint32_t index) const override {
+    uint32_t total_num_keys = get_num_keys().get();
+    ET_CHECK_OR_RETURN_ERROR(
+        index >= 0 && index < total_num_keys,
+        InvalidArgument,
+        "Index %u out of range of size %u",
+        index,
+        total_num_keys);
+
+    if (index < first_->get_num_keys().get()) {
+      return first_->get_key(index);
+    } else {
+      return second_->get_key(index - first_->get_num_keys().get());
+    }
+  }
+
+  MergedDataMap(MergedDataMap&&) noexcept = default;
+
+  ~MergedDataMap() override = default;
+
+ private:
+  MergedDataMap(const NamedDataMap* first, const NamedDataMap* second)
+      : first_{first}, second_{second} {}
+
+  // Not copyable or assignable.
+  MergedDataMap(const MergedDataMap& rhs) = delete;
+  MergedDataMap& operator=(MergedDataMap&& rhs) noexcept = delete;
+  MergedDataMap& operator=(const MergedDataMap& rhs) = delete;
+
+  const NamedDataMap* first_;
+  const NamedDataMap* second_;
+};
+
+} // namespace internal
+} // namespace ET_RUNTIME_NAMESPACE
+} // namespace executorch
diff --git a/runtime/executor/targets.bzl b/runtime/executor/targets.bzl
index 649b2c13cc1..98165373b73 100644
--- a/runtime/executor/targets.bzl
+++ b/runtime/executor/targets.bzl
@@ -69,6 +69,16 @@ def define_common_targets():
             exported_preprocessor_flags = [] if runtime.is_oss else ["-DEXECUTORCH_INTERNAL_FLATBUFFERS=1"],
         )
 
+        runtime.cxx_library(
+            name = "merged_data_map" + aten_suffix,
+            exported_headers = [
+                "merged_data_map.h",
+            ],
+            exported_deps = [
+                "//executorch/runtime/core:named_data_map" + aten_suffix,
+            ],
+        )
+
         runtime.cxx_library(
             name = "program" + aten_suffix,
             exported_deps = [
diff --git a/runtime/executor/test/merged_data_map_test.cpp b/runtime/executor/test/merged_data_map_test.cpp
new file mode 100644
index 00000000000..c9d1d510b97
--- /dev/null
+++ b/runtime/executor/test/merged_data_map_test.cpp
@@ -0,0 +1,148 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <executorch/extension/data_loader/file_data_loader.h>
+#include <executorch/extension/flat_tensor/flat_tensor_data_map.h>
+#include <executorch/runtime/core/error.h>
+#include <executorch/runtime/core/result.h>
+#include <executorch/runtime/executor/merged_data_map.h>
+#include <executorch/runtime/platform/runtime.h>
+
+#include <gtest/gtest.h>
+
+using namespace ::testing;
+using executorch::extension::FileDataLoader;
+using executorch::extension::FlatTensorDataMap;
+using executorch::runtime::DataLoader;
+using executorch::runtime::Error;
+using executorch::runtime::FreeableBuffer;
+using executorch::runtime::NamedDataMap;
+using executorch::runtime::Result;
+using executorch::runtime::TensorLayout;
+using executorch::runtime::internal::MergedDataMap;
+
+class MergedDataMapTest : public ::testing::Test {
+ protected:
+  void load_flat_tensor_data_map(const char* path, const char* module_name) {
+    Result<FileDataLoader> loader = FileDataLoader::from(path);
+    ASSERT_EQ(loader.error(), Error::Ok);
+    loaders_.insert(
+        {module_name,
+         std::make_unique<FileDataLoader>(std::move(loader.get()))});
+
+    Result<FlatTensorDataMap> data_map =
+        FlatTensorDataMap::load(loaders_[module_name].get());
+    EXPECT_EQ(data_map.error(), Error::Ok);
+
+    data_maps_.insert(
+        {module_name,
+         std::make_unique<FlatTensorDataMap>(std::move(data_map.get()))});
+  }
+
+  void SetUp() override {
+    // Since these tests cause ET_LOG to be called, the PAL must be initialized
+    // first.
+    executorch::runtime::runtime_init();
+
+    // Load FlatTensor data maps.
+    // The eager addmul and linear models are defined at:
+    // //executorch/test/models/export_program.py
+    load_flat_tensor_data_map(
+        std::getenv("ET_MODULE_ADD_MUL_DATA_PATH"), "addmul");
+    load_flat_tensor_data_map(
+        std::getenv("ET_MODULE_LINEAR_DATA_PATH"), "linear");
+  }
+
+ private:
+  // Must outlive data_maps_, but tests shouldn't need to touch it.
+  std::unordered_map<std::string, std::unique_ptr<FileDataLoader>> loaders_;
+
+ protected:
+  std::unordered_map<std::string, std::unique_ptr<NamedDataMap>> data_maps_;
+};
+
+// Check that two tensor layouts are equivalent.
+void check_tensor_layout(TensorLayout& layout1, TensorLayout& layout2) {
+  EXPECT_EQ(layout1.scalar_type(), layout2.scalar_type());
+  EXPECT_EQ(layout1.nbytes(), layout2.nbytes());
+  EXPECT_EQ(layout1.sizes().size(), layout2.sizes().size());
+  for (size_t i = 0; i < layout1.sizes().size(); i++) {
+    EXPECT_EQ(layout1.sizes()[i], layout2.sizes()[i]);
+  }
+  EXPECT_EQ(layout1.dim_order().size(), layout2.dim_order().size());
+  for (size_t i = 0; i < layout1.dim_order().size(); i++) {
+    EXPECT_EQ(layout1.dim_order()[i], layout2.dim_order()[i]);
+  }
+}
+
+// Given that ndm is part of merged, check that all the API calls on ndm produce
+// the same results as merged.
+void compare_ndm_api_calls(
+    const NamedDataMap* ndm,
+    const NamedDataMap* merged) {
+  uint32_t num_keys = ndm->get_num_keys().get();
+  for (uint32_t i = 0; i < num_keys; i++) {
+    auto key = ndm->get_key(i).get();
+
+    // Compare get_tensor_layout.
+    auto ndm_meta = ndm->get_tensor_layout(key).get();
+    auto merged_meta = merged->get_tensor_layout(key).get();
+    check_tensor_layout(ndm_meta, merged_meta);
+
+    // Coompare get_data.
+    auto ndm_data = ndm->get_data(key);
+    auto merged_data = merged->get_data(key);
+    EXPECT_EQ(ndm_data.get().size(), merged_data.get().size());
+    for (size_t j = 0; j < ndm_meta.nbytes(); j++) {
+      EXPECT_EQ(
+          ((uint8_t*)ndm_data.get().data())[j],
+          ((uint8_t*)merged_data.get().data())[j]);
+    }
+    ndm_data->Free();
+    merged_data->Free();
+  }
+}
+
+TEST_F(MergedDataMapTest, LoadNullDataMap) {
+  Result<MergedDataMap> merged_map = MergedDataMap::load(nullptr, nullptr);
+  EXPECT_EQ(merged_map.error(), Error::InvalidArgument);
+}
+
+TEST_F(MergedDataMapTest, LoadMultipleDataMaps) {
+  Result<MergedDataMap> merged_map = MergedDataMap::load(
+      data_maps_["addmul"].get(), data_maps_["linear"].get());
+  EXPECT_EQ(merged_map.error(), Error::Ok);
+}
+
+TEST_F(MergedDataMapTest, LoadDuplicateDataMapsFail) {
+  Result<MergedDataMap> merged_map = MergedDataMap::load(
+      data_maps_["addmul"].get(), data_maps_["addmul"].get());
+  EXPECT_EQ(merged_map.error(), Error::InvalidArgument);
+}
+
+TEST_F(MergedDataMapTest, CheckDataMapContents) {
+  Result<MergedDataMap> merged_map = MergedDataMap::load(
+      data_maps_["addmul"].get(), data_maps_["linear"].get());
+  EXPECT_EQ(merged_map.error(), Error::Ok);
+
+  // Num keys.
+  size_t addmul_num_keys = data_maps_["addmul"]->get_num_keys().get();
+  size_t linear_num_keys = data_maps_["linear"]->get_num_keys().get();
+  EXPECT_EQ(
+      merged_map->get_num_keys().get(), addmul_num_keys + linear_num_keys);
+
+  // Load data into is not implemented for the merged data map.
+  void* memory_block = malloc(10);
+  ASSERT_EQ(
+      Error::NotImplemented, merged_map->load_data_into("a", memory_block, 10));
+  free(memory_block);
+
+  // API calls produce equivalent results.
+  compare_ndm_api_calls(data_maps_["addmul"].get(), &merged_map.get());
+  compare_ndm_api_calls(data_maps_["linear"].get(), &merged_map.get());
+}
diff --git a/runtime/executor/test/targets.bzl b/runtime/executor/test/targets.bzl
index 39ff0668d5d..7b4672e4414 100644
--- a/runtime/executor/test/targets.bzl
+++ b/runtime/executor/test/targets.bzl
@@ -125,6 +125,7 @@ def define_common_targets(is_fbcode = False):
             "ET_MODULE_STATEFUL_PATH": "$(location fbcode//executorch/test/models:exported_programs[ModuleStateful.pte])",
             "ET_MODULE_ADD_MUL_PROGRAM_PATH": "$(location fbcode//executorch/test/models:exported_program_and_data[ModuleAddMul.pte])",
             "ET_MODULE_ADD_MUL_DATA_PATH": "$(location fbcode//executorch/test/models:exported_program_and_data[ModuleAddMul.ptd])",
+            "ET_MODULE_LINEAR_DATA_PATH": "$(location fbcode//executorch/test/models:exported_program_and_data[ModuleLinear.ptd])",
         }
 
         runtime.cxx_test(
@@ -142,6 +143,19 @@ def define_common_targets(is_fbcode = False):
             env = modules_env,
         )
 
+        runtime.cxx_test(
+            name = "merged_data_map_test",
+            srcs = [
+                "merged_data_map_test.cpp",
+            ],
+            deps = [
+                "//executorch/extension/data_loader:file_data_loader",
+                "//executorch/extension/flat_tensor:flat_tensor_data_map",
+                "//executorch/runtime/executor:merged_data_map",
+            ],
+            env = modules_env,
+        )
+
         runtime.cxx_test(
             name = "method_test",
             srcs = [