diff --git a/ci/licenses_golden/licenses_flutter b/ci/licenses_golden/licenses_flutter
index 45901aa51c07e..d004764ca7ec7 100755
--- a/ci/licenses_golden/licenses_flutter
+++ b/ci/licenses_golden/licenses_flutter
@@ -2109,8 +2109,6 @@ FILE: ../../../flutter/third_party/accessibility/base/simple_token.h
 FILE: ../../../flutter/third_party/accessibility/base/string_utils.cc
 FILE: ../../../flutter/third_party/accessibility/base/string_utils.h
 FILE: ../../../flutter/third_party/accessibility/base/string_utils_unittest.cc
-FILE: ../../../flutter/third_party/accessibility/base/win/string_conversion.cc
-FILE: ../../../flutter/third_party/accessibility/base/win/string_conversion.h
 FILE: ../../../flutter/third_party/accessibility/gfx/transform.cc
 FILE: ../../../flutter/third_party/accessibility/gfx/transform.h
 FILE: ../../../flutter/third_party/tonic/common/build_config.h
diff --git a/third_party/accessibility/base/BUILD.gn b/third_party/accessibility/base/BUILD.gn
index 0897fa07224b0..54b0a47af32ef 100644
--- a/third_party/accessibility/base/BUILD.gn
+++ b/third_party/accessibility/base/BUILD.gn
@@ -35,8 +35,6 @@ source_set("base") {
       "win/scoped_safearray.h",
       "win/scoped_variant.cc",
       "win/scoped_variant.h",
-      "win/string_conversion.cc",
-      "win/string_conversion.h",
       "win/variant_util.h",
       "win/variant_vector.cc",
       "win/variant_vector.h",
@@ -52,6 +50,7 @@ source_set("base") {
 
   public_deps = [
     "numerics",
+    "//flutter/fml:string_conversion",
     "//flutter/third_party/accessibility/ax_build",
     "//third_party/dart/runtime/third_party/double-conversion/src:libdouble_conversion",
   ]
diff --git a/third_party/accessibility/base/string_utils.cc b/third_party/accessibility/base/string_utils.cc
index 0152bbcbef65e..61e0a4a257f4a 100644
--- a/third_party/accessibility/base/string_utils.cc
+++ b/third_party/accessibility/base/string_utils.cc
@@ -11,12 +11,9 @@
 #include <regex>
 #include <sstream>
 
+#include "flutter/fml/string_conversion.h"
 #include "third_party/dart/runtime/third_party/double-conversion/src/double-conversion.h"
 
-#if defined(_WIN32)
-#include "base/win/string_conversion.h"
-#endif
-
 #include "no_destructor.h"
 
 namespace base {
@@ -68,21 +65,11 @@ std::u16string ASCIIToUTF16(std::string src) {
 }
 
 std::u16string UTF8ToUTF16(std::string src) {
-#if defined(_WIN32)
-  return WideToUTF16(win::Utf16FromUtf8(src));
-#else
-  std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t> convert;
-  return convert.from_bytes(src);
-#endif
+  return fml::Utf8ToUtf16(src);
 }
 
 std::string UTF16ToUTF8(std::u16string src) {
-#if defined(_WIN32)
-  return win::Utf8FromUtf16(UTF16ToWide(src));
-#else
-  std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t> convert;
-  return convert.to_bytes(src);
-#endif
+  return fml::Utf16ToUtf8(src);
 }
 
 std::u16string WideToUTF16(const std::wstring& src) {
diff --git a/third_party/accessibility/base/win/string_conversion.cc b/third_party/accessibility/base/win/string_conversion.cc
deleted file mode 100644
index 15bff3ce7b17a..0000000000000
--- a/third_party/accessibility/base/win/string_conversion.cc
+++ /dev/null
@@ -1,60 +0,0 @@
-// Copyright 2013 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// TODO(gw280): This is copied from shell/platform/win. When
-// https://github.com/flutter/flutter/issues/75653 is fixed, we should
-// deduplicate these and put them in fml.
-#include "string_conversion.h"
-
-#include <Windows.h>
-
-namespace base {
-namespace win {
-
-std::string Utf8FromUtf16(const std::wstring& utf16_string) {
-  if (utf16_string.empty()) {
-    return std::string();
-  }
-  int target_length = ::WideCharToMultiByte(
-      CP_UTF8, WC_ERR_INVALID_CHARS, utf16_string.data(),
-      static_cast<int>(utf16_string.length()), nullptr, 0, nullptr, nullptr);
-  if (target_length == 0) {
-    return std::string();
-  }
-  std::string utf8_string;
-  utf8_string.resize(target_length);
-  int converted_length = ::WideCharToMultiByte(
-      CP_UTF8, WC_ERR_INVALID_CHARS, utf16_string.data(),
-      static_cast<int>(utf16_string.length()), utf8_string.data(),
-      target_length, nullptr, nullptr);
-  if (converted_length == 0) {
-    return std::string();
-  }
-  return utf8_string;
-}
-
-std::wstring Utf16FromUtf8(const std::string& utf8_string) {
-  if (utf8_string.empty()) {
-    return std::wstring();
-  }
-  int target_length =
-      ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, utf8_string.data(),
-                            static_cast<int>(utf8_string.length()), nullptr, 0);
-  if (target_length == 0) {
-    return std::wstring();
-  }
-  std::wstring utf16_string;
-  utf16_string.resize(target_length);
-  int converted_length =
-      ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, utf8_string.data(),
-                            static_cast<int>(utf8_string.length()),
-                            utf16_string.data(), target_length);
-  if (converted_length == 0) {
-    return std::wstring();
-  }
-  return utf16_string;
-}
-
-}  // namespace win
-}  // namespace base
diff --git a/third_party/accessibility/base/win/string_conversion.h b/third_party/accessibility/base/win/string_conversion.h
deleted file mode 100644
index 471268f4d046a..0000000000000
--- a/third_party/accessibility/base/win/string_conversion.h
+++ /dev/null
@@ -1,24 +0,0 @@
-// Copyright 2013 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef FLUTTER_SHELL_PLATFORM_WINDOWS_STRING_CONVERSION_H_
-#define FLUTTER_SHELL_PLATFORM_WINDOWS_STRING_CONVERSION_H_
-
-#include <string>
-
-namespace base {
-namespace win {
-
-// Converts a string from UTF-16 to UTF-8. Returns an empty string if the
-// input is not valid UTF-16.
-std::string Utf8FromUtf16(const std::wstring& utf16_string);
-
-// Converts a string from UTF-8 to UTF-16. Returns an empty string if the
-// input is not valid UTF-8.
-std::wstring Utf16FromUtf8(const std::string& utf8_string);
-
-}  // namespace win
-}  // namespace base
-
-#endif  // FLUTTER_SHELL_PLATFORM_WINDOWS_STRING_CONVERSION_H_