diff --git a/base/file.cpp b/base/file.cpp
index 3dfcfbb..b1ddc5d 100644
--- a/base/file.cpp
+++ b/base/file.cpp
@@ -49,29 +49,41 @@
 #include "android-base/unique_fd.h"
 #include "android-base/utf8.h"
 
+namespace {
+
 #ifdef _WIN32
-int mkstemp(char* template_name) {
-  if (_mktemp(template_name) == nullptr) {
+static int mkstemp(char* name_template, size_t size_in_chars) {
+  auto path = name_template;
+  if (_mktemp_s(path, size_in_chars) != 0) {
     return -1;
   }
+
+  std::wstring path_wide;
+  CHECK(android::base::UTF8ToWide(path, &path_wide))
+      << "path can't be converted to wchar: " << path;
+
   // Use open() to match the close() that TemporaryFile's destructor does.
   // Use O_BINARY to match base file APIs.
-  return open(template_name, O_CREAT | O_EXCL | O_RDWR | O_BINARY, S_IRUSR | S_IWUSR);
+  return _wopen(path_wide.c_str(), O_CREAT | O_EXCL | O_RDWR | O_BINARY, S_IRUSR | S_IWUSR);
 }
 
-char* mkdtemp(char* template_name) {
-  if (_mktemp(template_name) == nullptr) {
+static char* mkdtemp(char* name_template, size_t size_in_chars) {
+  auto path = name_template;
+  if (_mktemp_s(path, size_in_chars) != 0) {
     return nullptr;
   }
-  if (_mkdir(template_name) == -1) {
+
+  std::wstring path_wide;
+  CHECK(android::base::UTF8ToWide(path, &path_wide))
+      << "path can't be converted to wchar: " << path;
+
+  if (_wmkdir(path_wide.c_str()) != 0) {
     return nullptr;
   }
-  return template_name;
+  return path;
 }
 #endif
 
-namespace {
-
 std::string GetSystemTempDir() {
 #if defined(__ANDROID__)
   const auto* tmpdir = getenv("TMPDIR");
@@ -83,15 +95,20 @@
   // so try current directory if /data/local/tmp is not accessible.
   return ".";
 #elif defined(_WIN32)
-  char tmp_dir[MAX_PATH];
-  DWORD result = GetTempPathA(sizeof(tmp_dir), tmp_dir);  // checks TMP env
-  CHECK_NE(result, 0ul) << "GetTempPathA failed, error: " << GetLastError();
-  CHECK_LT(result, sizeof(tmp_dir)) << "path truncated to: " << result;
+  wchar_t tmp_dir_w[MAX_PATH];
+  DWORD result = GetTempPathW(std::size(tmp_dir_w), tmp_dir_w);  // checks TMP env
+  CHECK_NE(result, 0ul) << "GetTempPathW failed, error: " << GetLastError();
+  CHECK_LT(result, std::size(tmp_dir_w)) << "path truncated to: " << result;
 
   // GetTempPath() returns a path with a trailing slash, but init()
   // does not expect that, so remove it.
-  CHECK_EQ(tmp_dir[result - 1], '\\');
-  tmp_dir[result - 1] = '\0';
+  if (tmp_dir_w[result - 1] == L'\\') {
+    tmp_dir_w[result - 1] = L'\0';
+  }
+
+  std::string tmp_dir;
+  CHECK(android::base::WideToUTF8(tmp_dir_w, &tmp_dir)) << "path can't be converted to utf8";
+
   return tmp_dir;
 #else
   const auto* tmpdir = getenv("TMPDIR");
@@ -127,7 +144,11 @@
 
 void TemporaryFile::init(const std::string& tmp_dir) {
   snprintf(path, sizeof(path), "%s%cTemporaryFile-XXXXXX", tmp_dir.c_str(), OS_PATH_SEPARATOR);
+#if defined(_WIN32)
+  fd = mkstemp(path, sizeof(path));
+#else
   fd = mkstemp(path);
+#endif
 }
 
 TemporaryDir::TemporaryDir() {
@@ -167,7 +188,11 @@
 
 bool TemporaryDir::init(const std::string& tmp_dir) {
   snprintf(path, sizeof(path), "%s%cTemporaryDir-XXXXXX", tmp_dir.c_str(), OS_PATH_SEPARATOR);
+#if defined(_WIN32)
+  return (mkdtemp(path, sizeof(path)) != nullptr);
+#else
   return (mkdtemp(path) != nullptr);
+#endif
 }
 
 namespace android {
diff --git a/base/file_test.cpp b/base/file_test.cpp
index f64e81c..65ee235 100644
--- a/base/file_test.cpp
+++ b/base/file_test.cpp
@@ -16,18 +16,25 @@
 
 #include "android-base/file.h"
 
+#include "android-base/utf8.h"
+
 #include <gtest/gtest.h>
 
 #include <errno.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <wchar.h>
 
 #include <string>
 
 #if !defined(_WIN32)
 #include <pwd.h>
+#else
+#include <processenv.h>
 #endif
 
+#include "android-base/logging.h"  // and must be after windows.h for ERROR
+
 TEST(file, ReadFileToString_ENOENT) {
   std::string s("hello");
   errno = 0;
@@ -38,7 +45,7 @@
 
 TEST(file, ReadFileToString_WriteStringToFile) {
   TemporaryFile tf;
-  ASSERT_TRUE(tf.fd != -1);
+  ASSERT_NE(tf.fd, -1) << tf.path;
   ASSERT_TRUE(android::base::WriteStringToFile("abc", tf.path))
     << strerror(errno);
   std::string s;
@@ -70,7 +77,7 @@
 #if !defined(_WIN32)
 TEST(file, WriteStringToFile2) {
   TemporaryFile tf;
-  ASSERT_TRUE(tf.fd != -1);
+  ASSERT_NE(tf.fd, -1) << tf.path;
   ASSERT_TRUE(android::base::WriteStringToFile("abc", tf.path, 0660,
                                                getuid(), getgid()))
       << strerror(errno);
@@ -86,9 +93,83 @@
 }
 #endif
 
+#if defined(_WIN32)
+TEST(file, NonUnicodeCharsWindows) {
+  constexpr auto kMaxEnvVariableValueSize = 32767;
+  std::wstring old_tmp;
+  old_tmp.resize(kMaxEnvVariableValueSize);
+  old_tmp.resize(GetEnvironmentVariableW(L"TMP", old_tmp.data(), old_tmp.size()));
+  std::wstring new_tmp = old_tmp;
+  if (new_tmp.back() != L'\\') {
+    new_tmp.push_back(L'\\');
+  }
+
+  {
+    auto path(new_tmp + L"锦绣成都\\");
+    _wmkdir(path.c_str());
+    ASSERT_TRUE(SetEnvironmentVariableW(L"TMP", path.c_str()));
+
+    TemporaryFile tf;
+    ASSERT_NE(tf.fd, -1) << tf.path;
+    ASSERT_TRUE(android::base::WriteStringToFd("abc", tf.fd));
+
+    ASSERT_EQ(0, lseek(tf.fd, 0, SEEK_SET)) << strerror(errno);
+
+    std::string s;
+    ASSERT_TRUE(android::base::ReadFdToString(tf.fd, &s)) << strerror(errno);
+    EXPECT_EQ("abc", s);
+  }
+  {
+    auto path(new_tmp + L"директория с длинным именем\\");
+    _wmkdir(path.c_str());
+    ASSERT_TRUE(SetEnvironmentVariableW(L"TMP", path.c_str()));
+
+    TemporaryFile tf;
+    ASSERT_NE(tf.fd, -1) << tf.path;
+    ASSERT_TRUE(android::base::WriteStringToFd("abc", tf.fd));
+
+    ASSERT_EQ(0, lseek(tf.fd, 0, SEEK_SET)) << strerror(errno);
+
+    std::string s;
+    ASSERT_TRUE(android::base::ReadFdToString(tf.fd, &s)) << strerror(errno);
+    EXPECT_EQ("abc", s);
+  }
+  {
+    auto path(new_tmp + L"äüöß weiß\\");
+    _wmkdir(path.c_str());
+    ASSERT_TRUE(SetEnvironmentVariableW(L"TMP", path.c_str()));
+
+    TemporaryFile tf;
+    ASSERT_NE(tf.fd, -1) << tf.path;
+    ASSERT_TRUE(android::base::WriteStringToFd("abc", tf.fd));
+
+    ASSERT_EQ(0, lseek(tf.fd, 0, SEEK_SET)) << strerror(errno);
+
+    std::string s;
+    ASSERT_TRUE(android::base::ReadFdToString(tf.fd, &s)) << strerror(errno);
+    EXPECT_EQ("abc", s);
+  }
+
+  SetEnvironmentVariableW(L"TMP", old_tmp.c_str());
+}
+
+TEST(file, RootDirectoryWindows) {
+  constexpr auto kMaxEnvVariableValueSize = 32767;
+  std::wstring old_tmp;
+  old_tmp.resize(kMaxEnvVariableValueSize);
+  old_tmp.resize(GetEnvironmentVariableW(L"TMP", old_tmp.data(), old_tmp.size()));
+  SetEnvironmentVariableW(L"TMP", L"C:");
+
+  TemporaryFile tf;
+  ASSERT_NE(tf.fd, -1) << tf.path;
+
+  SetEnvironmentVariableW(L"TMP", old_tmp.c_str());
+}
+#endif
+
 TEST(file, WriteStringToFd) {
   TemporaryFile tf;
-  ASSERT_TRUE(tf.fd != -1);
+  ASSERT_NE(tf.fd, -1) << tf.path;
   ASSERT_TRUE(android::base::WriteStringToFd("abc", tf.fd));
 
   ASSERT_EQ(0, lseek(tf.fd, 0, SEEK_SET)) << strerror(errno);
@@ -100,7 +181,7 @@
 
 TEST(file, WriteFully) {
   TemporaryFile tf;
-  ASSERT_TRUE(tf.fd != -1);
+  ASSERT_NE(tf.fd, -1) << tf.path;
   ASSERT_TRUE(android::base::WriteFully(tf.fd, "abc", 3));
 
   ASSERT_EQ(0, lseek(tf.fd, 0, SEEK_SET)) << strerror(errno);
@@ -119,7 +200,7 @@
 
 TEST(file, RemoveFileIfExists) {
   TemporaryFile tf;
-  ASSERT_TRUE(tf.fd != -1);
+  ASSERT_NE(tf.fd, -1) << tf.path;
   close(tf.fd);
   tf.fd = -1;
   std::string err;
@@ -253,7 +334,7 @@
 
 TEST(file, ReadFileToString_capacity) {
   TemporaryFile tf;
-  ASSERT_TRUE(tf.fd != -1);
+  ASSERT_NE(tf.fd, -1) << tf.path;
 
   // For a huge file, the overhead should still be small.
   std::string s;
@@ -280,7 +361,7 @@
 
 TEST(file, ReadFileToString_capacity_0) {
   TemporaryFile tf;
-  ASSERT_TRUE(tf.fd != -1);
+  ASSERT_NE(tf.fd, -1) << tf.path;
 
   // Because /proc reports its files as zero-length, we don't actually trust
   // any file that claims to be zero-length. Rather than add increasingly