diff --git a/onnxruntime/core/framework/ex_lib_loader.cc b/onnxruntime/core/framework/ex_lib_loader.cc
index 7070cbf9f1..66f53db3db 100644
--- a/onnxruntime/core/framework/ex_lib_loader.cc
+++ b/onnxruntime/core/framework/ex_lib_loader.cc
@@ -38,7 +38,8 @@ common::Status ExLibLoader::LoadExternalLib(const std::string& dso_file_path,
     }
 
     void* lib_handle = nullptr;
-    ORT_RETURN_IF_ERROR(Env::Default().LoadDynamicLibrary(dso_file_path, false, &lib_handle));
+    auto path_str = ToPathString(dso_file_path);
+    ORT_RETURN_IF_ERROR(Env::Default().LoadDynamicLibrary(path_str, false, &lib_handle));
     dso_name_data_map_[dso_file_path] = lib_handle;
     *handle = lib_handle;
     return Status::OK();
diff --git a/onnxruntime/core/platform/env.h b/onnxruntime/core/platform/env.h
index 369e492292..14c82096b6 100644
--- a/onnxruntime/core/platform/env.h
+++ b/onnxruntime/core/platform/env.h
@@ -230,7 +230,7 @@ class Env {
   // OK from the function.
   // Otherwise returns nullptr in "*handle" and an error status from the
   // function.
-  virtual common::Status LoadDynamicLibrary(const std::string& library_filename, bool global_symbols, void** handle) const = 0;
+  virtual common::Status LoadDynamicLibrary(const PathString& library_filename, bool global_symbols, void** handle) const = 0;
 
   virtual common::Status UnloadDynamicLibrary(void* handle) const = 0;
 
@@ -238,7 +238,7 @@ class Env {
   //
   // Used to help load other shared libraries that live in the same folder as the core code, for example
   // The DNNL provider shared library. Without this path, the module won't be found on windows in all cases.
-  virtual std::string GetRuntimePath() const { return ""; }
+  virtual PathString GetRuntimePath() const { return PathString(); }
 
   // \brief Get a pointer to a symbol from a dynamic library.
   //
diff --git a/onnxruntime/core/platform/posix/env.cc b/onnxruntime/core/platform/posix/env.cc
index 0fe754c173..d055e78af3 100644
--- a/onnxruntime/core/platform/posix/env.cc
+++ b/onnxruntime/core/platform/posix/env.cc
@@ -529,7 +529,7 @@ class PosixEnv : public Env {
     return Status::OK();
   }
 
-  common::Status LoadDynamicLibrary(const std::string& library_filename, bool global_symbols, void** handle) const override {
+  common::Status LoadDynamicLibrary(const PathString& library_filename, bool global_symbols, void** handle) const override {
     dlerror();  // clear any old error_str
     *handle = dlopen(library_filename.c_str(), RTLD_NOW | (global_symbols ? RTLD_GLOBAL : RTLD_LOCAL));
     char* error_str = dlerror();
diff --git a/onnxruntime/core/platform/windows/env.cc b/onnxruntime/core/platform/windows/env.cc
index eacb1e86fa..2eaf3fb107 100644
--- a/onnxruntime/core/platform/windows/env.cc
+++ b/onnxruntime/core/platform/windows/env.cc
@@ -653,22 +653,26 @@ common::Status WindowsEnv::GetCanonicalPath(
 
 // Return the path of the executable/shared library for the current running code. This is to make it
 // possible to load other shared libraries installed next to our core runtime code.
-std::string WindowsEnv::GetRuntimePath() const {
-  char buffer[MAX_PATH];
-  if (!GetModuleFileNameA(reinterpret_cast<HINSTANCE>(&__ImageBase), buffer, _countof(buffer)))
-    return "";
+PathString WindowsEnv::GetRuntimePath() const {
+  wchar_t buffer[MAX_PATH];
+  if (!GetModuleFileNameW(reinterpret_cast<HINSTANCE>(&__ImageBase), buffer, _countof(buffer))) {
+    return PathString();
+  }
 
   // Remove the filename at the end, but keep the trailing slash
-  std::string path(buffer);
-  auto slash_index = path.find_last_of('\\');
-  if (slash_index == std::string::npos)
-    return "";
-
+  PathString path(buffer);
+  auto slash_index = path.find_last_of(ORT_TSTR('\\'));
+  if (slash_index == std::string::npos) {
+    // Windows supports forward slashes
+    slash_index = path.find_last_of(ORT_TSTR('/'));
+    if (slash_index == std::string::npos) {
+      return PathString();
+    }
+  }
   return path.substr(0, slash_index + 1);
 }
 
-Status WindowsEnv::LoadDynamicLibrary(const std::string& library_filename, bool /*global_symbols*/, void** handle) const {
-  const std::wstring& wlibrary_filename = ToWideString(library_filename);
+Status WindowsEnv::LoadDynamicLibrary(const PathString& wlibrary_filename, bool /*global_symbols*/, void** handle) const {
 #if WINAPI_FAMILY == WINAPI_FAMILY_PC_APP
   *handle = ::LoadPackagedLibrary(wlibrary_filename.c_str(), 0);
 #else
diff --git a/onnxruntime/core/platform/windows/env.h b/onnxruntime/core/platform/windows/env.h
index 5dd79007a8..c54a552b6f 100644
--- a/onnxruntime/core/platform/windows/env.h
+++ b/onnxruntime/core/platform/windows/env.h
@@ -76,8 +76,8 @@ class WindowsEnv : public Env {
   common::Status FileOpenWr(const std::string& path, /*out*/ int& fd) const override;
   common::Status FileClose(int fd) const override;
   common::Status GetCanonicalPath(const PathString& path, PathString& canonical_path) const override;
-  std::string GetRuntimePath() const override;
-  Status LoadDynamicLibrary(const std::string& library_filename, bool /*global_symbols*/, void** handle) const override;
+  PathString GetRuntimePath() const override;
+  Status LoadDynamicLibrary(const PathString& library_filename, bool /*global_symbols*/, void** handle) const override;
   Status UnloadDynamicLibrary(void* handle) const override;
   Status GetSymbolFromLibrary(void* handle, const std::string& symbol_name, void** symbol) const override;
   std::string FormatLibraryFileName(const std::string& name, const std::string& version) const override;
diff --git a/onnxruntime/core/session/onnxruntime_c_api.cc b/onnxruntime/core/session/onnxruntime_c_api.cc
index 9a3411bb15..7a9666be54 100644
--- a/onnxruntime/core/session/onnxruntime_c_api.cc
+++ b/onnxruntime/core/session/onnxruntime_c_api.cc
@@ -600,7 +600,8 @@ ORT_API_STATUS_IMPL(OrtApis::AddCustomOpDomain, _Inout_ OrtSessionOptions* optio
 ORT_API_STATUS_IMPL(OrtApis::RegisterCustomOpsLibrary, _Inout_ OrtSessionOptions* options, _In_ const char* library_path, _Outptr_ void** library_handle) {
   API_IMPL_BEGIN
 
-  ORT_API_RETURN_IF_STATUS_NOT_OK(Env::Default().LoadDynamicLibrary(library_path, false, library_handle));
+  auto path_str = ToPathString(library_path);
+  ORT_API_RETURN_IF_STATUS_NOT_OK(Env::Default().LoadDynamicLibrary(path_str, false, library_handle));
   if (!*library_handle)
     return OrtApis::CreateStatus(ORT_FAIL, "RegisterCustomOpsLibrary: Failed to load library");
 
diff --git a/onnxruntime/core/session/provider_bridge_ort.cc b/onnxruntime/core/session/provider_bridge_ort.cc
index ae7cdf757f..db0777fe88 100644
--- a/onnxruntime/core/session/provider_bridge_ort.cc
+++ b/onnxruntime/core/session/provider_bridge_ort.cc
@@ -90,7 +90,7 @@ using IndexedSubGraph_MetaDef = IndexedSubGraph::MetaDef;
 // The filename extension for a shared library is different per platform
 #ifdef _WIN32
 #define LIBRARY_PREFIX
-#define LIBRARY_EXTENSION ".dll"
+#define LIBRARY_EXTENSION ORT_TSTR(".dll")
 #elif defined(__APPLE__)
 #define LIBRARY_PREFIX "lib"
 #define LIBRARY_EXTENSION ".dylib"
@@ -1049,7 +1049,8 @@ struct ProviderSharedLibrary {
     if (handle_)
       return;
 
-    std::string full_path = Env::Default().GetRuntimePath() + std::string(LIBRARY_PREFIX "onnxruntime_providers_shared" LIBRARY_EXTENSION);
+    auto full_path = Env::Default().GetRuntimePath() + 
+      PathString(LIBRARY_PREFIX ORT_TSTR("onnxruntime_providers_shared") LIBRARY_EXTENSION);
     ORT_THROW_IF_ERROR(Env::Default().LoadDynamicLibrary(full_path, true /*shared_globals on unix*/, &handle_));
 
     void (*PProvider_SetHost)(void*);
@@ -1089,7 +1090,7 @@ bool InitProvidersSharedLibrary() try {
 }
 
 struct ProviderLibrary {
-  ProviderLibrary(const char* filename, bool unload = true) : filename_{filename}, unload_{unload} {}
+  ProviderLibrary(const ORTCHAR_T* filename, bool unload = true) : filename_{filename}, unload_{unload} {}
   ~ProviderLibrary() {
     // assert(!handle_); // We should already be unloaded at this point (disabled until Python shuts down deterministically)
   }
@@ -1100,7 +1101,7 @@ struct ProviderLibrary {
       if (!provider_) {
         s_library_shared.Ensure();
 
-        std::string full_path = Env::Default().GetRuntimePath() + std::string(filename_);
+        auto full_path = Env::Default().GetRuntimePath() + filename_;
         ORT_THROW_IF_ERROR(Env::Default().LoadDynamicLibrary(full_path, false, &handle_));
 
         Provider* (*PGetProvider)();
@@ -1139,7 +1140,7 @@ struct ProviderLibrary {
 
  private:
   std::mutex mutex_;
-  const char* filename_;
+  const ORTCHAR_T* filename_;
   bool unload_;
   Provider* provider_{};
   void* handle_{};
@@ -1147,28 +1148,28 @@ struct ProviderLibrary {
   ORT_DISALLOW_COPY_AND_ASSIGNMENT(ProviderLibrary);
 };
 
-static ProviderLibrary s_library_cuda(LIBRARY_PREFIX "onnxruntime_providers_cuda" LIBRARY_EXTENSION
+static ProviderLibrary s_library_cuda(LIBRARY_PREFIX ORT_TSTR("onnxruntime_providers_cuda") LIBRARY_EXTENSION
 #ifndef _WIN32
                                       ,
                                       false /* unload - On Linux if we unload the cuda shared provider we crash */
 #endif
 );
-static ProviderLibrary s_library_cann(LIBRARY_PREFIX "onnxruntime_providers_cann" LIBRARY_EXTENSION
+static ProviderLibrary s_library_cann(LIBRARY_PREFIX ORT_TSTR("onnxruntime_providers_cann") LIBRARY_EXTENSION
 #ifndef _WIN32
                                       ,
                                       false /* unload - On Linux if we unload the cann shared provider we crash */
 #endif
 );
-static ProviderLibrary s_library_rocm(LIBRARY_PREFIX "onnxruntime_providers_rocm" LIBRARY_EXTENSION
+static ProviderLibrary s_library_rocm(LIBRARY_PREFIX ORT_TSTR("onnxruntime_providers_rocm") LIBRARY_EXTENSION
 #ifndef _WIN32
                                       ,
                                       false /* unload - On Linux if we unload the rocm shared provider we crash */
 #endif
 );
-static ProviderLibrary s_library_dnnl(LIBRARY_PREFIX "onnxruntime_providers_dnnl" LIBRARY_EXTENSION);
-static ProviderLibrary s_library_openvino(LIBRARY_PREFIX "onnxruntime_providers_openvino" LIBRARY_EXTENSION);
-static ProviderLibrary s_library_tensorrt(LIBRARY_PREFIX "onnxruntime_providers_tensorrt" LIBRARY_EXTENSION);
-static ProviderLibrary s_library_migraphx(LIBRARY_PREFIX "onnxruntime_providers_migraphx" LIBRARY_EXTENSION);
+static ProviderLibrary s_library_dnnl(LIBRARY_PREFIX ORT_TSTR("onnxruntime_providers_dnnl") LIBRARY_EXTENSION);
+static ProviderLibrary s_library_openvino(LIBRARY_PREFIX ORT_TSTR("onnxruntime_providers_openvino") LIBRARY_EXTENSION);
+static ProviderLibrary s_library_tensorrt(LIBRARY_PREFIX ORT_TSTR("onnxruntime_providers_tensorrt") LIBRARY_EXTENSION);
+static ProviderLibrary s_library_migraphx(LIBRARY_PREFIX ORT_TSTR("onnxruntime_providers_migraphx") LIBRARY_EXTENSION);
 
 void UnloadSharedProviders() {
   s_library_dnnl.Unload();
diff --git a/onnxruntime/python/onnxruntime_pybind_state.cc b/onnxruntime/python/onnxruntime_pybind_state.cc
index 27bbfde16a..995977c5f7 100644
--- a/onnxruntime/python/onnxruntime_pybind_state.cc
+++ b/onnxruntime/python/onnxruntime_pybind_state.cc
@@ -13,6 +13,7 @@
 #include "core/common/logging/logging.h"
 #include "core/common/logging/severity.h"
 #include "core/common/optional.h"
+#include "core/common/path_string.h"
 #include "core/framework/arena_extend_strategy.h"
 #include "core/framework/data_transfer_utils.h"
 #include "core/framework/data_types_internal.h"
@@ -77,7 +78,8 @@ static Env& platform_env = Env::Default();
 
 CustomOpLibrary::CustomOpLibrary(const char* library_path, OrtSessionOptions& ort_so) {
   {
-    OrtPybindThrowIfError(platform_env.LoadDynamicLibrary(library_path, false, &library_handle_));
+    const auto path_str = ToPathString(library_path);
+    OrtPybindThrowIfError(platform_env.LoadDynamicLibrary(path_str, false, &library_handle_));
 
     OrtStatus*(ORT_API_CALL * RegisterCustomOps)(OrtSessionOptions * options, const OrtApiBase* api);
 
@@ -311,7 +313,8 @@ static std::unique_ptr<onnxruntime::IExecutionProvider> LoadExecutionProvider(
     const ProviderOptions& provider_options = {},
     const std::string& entry_symbol_name = "GetProvider") {
   void* handle;
-  auto error = Env::Default().LoadDynamicLibrary(ep_shared_lib_path, false, &handle);
+  const auto path_str = ToPathString(ep_shared_lib_path);
+  auto error = Env::Default().LoadDynamicLibrary(path_str, false, &handle);
   if (!error.IsOK()) {
     throw std::runtime_error(error.ErrorMessage());
   }
diff --git a/orttraining/orttraining/python/orttraining_python_module.cc b/orttraining/orttraining/python/orttraining_python_module.cc
index 8ba48cd14e..0049932826 100644
--- a/orttraining/orttraining/python/orttraining_python_module.cc
+++ b/orttraining/orttraining/python/orttraining_python_module.cc
@@ -6,6 +6,7 @@
 
 #include "core/common/logging/logging.h"
 #include "core/common/logging/severity.h"
+#include "core/common/path_string.h"
 #include "core/providers/get_execution_providers.h"
 #include "core/session/provider_bridge_ort.h"
 
@@ -49,7 +50,8 @@ bool GetDyanmicExecutionProviderHash(
     size_t& hash,
     const std::string& entry_symbol_name = "ProviderHashFunc") {
   void* handle;
-  auto error = Env::Default().LoadDynamicLibrary(ep_shared_lib_path, false, &handle);
+  const auto path_str = ToPathString(ep_shared_lib_path);
+  auto error = Env::Default().LoadDynamicLibrary(path_str, false, &handle);
   if (!error.IsOK()) {
     throw std::runtime_error(error.ErrorMessage());
   }