diff --git a/crypto/bio/bio_test.cc b/crypto/bio/bio_test.cc
index 9328b4ead9..0c9f904e30 100644
--- a/crypto/bio/bio_test.cc
+++ b/crypto/bio/bio_test.cc
@@ -50,6 +50,8 @@ using Socket = int;
 #define INVALID_SOCKET (-1)
 static int closesocket(int sock) { return close(sock); }
 static std::string LastSocketError() { return strerror(errno); }
+static const int kOpenReadOnlyBinary = O_RDONLY;
+static const int kOpenReadOnlyText = O_RDONLY;
 #else
 using Socket = SOCKET;
 static std::string LastSocketError() {
@@ -57,6 +59,8 @@ static std::string LastSocketError() {
   snprintf(buf, sizeof(buf), "%d", WSAGetLastError());
   return buf;
 }
+static const int kOpenReadOnlyBinary = _O_RDONLY | _O_BINARY;
+static const int kOpenReadOnlyText = O_RDONLY | _O_TEXT;
 #endif
 
 class OwnedSocket {
@@ -832,21 +836,87 @@ TEST(BIOTest, ExternalData) {
 }
 
 // Test that, on Windows, |BIO_read_filename| opens files in binary mode.
-TEST(BIOTest, BinaryMode) {
+TEST(BIOTest, FileMode) {
   if (SkipTempFileTests()) {
     GTEST_SKIP();
   }
 
-  TemporaryFile file;
-  ASSERT_TRUE(file.Init("\r\n"));
+  TemporaryFile temp;
+  ASSERT_TRUE(temp.Init("hello\r\nworld"));
 
-  // Reading from the file should give back the exact bytes we put in.
+  auto expect_file_contents = [](BIO *bio, const std::string &str) {
+    // Read more than expected, to make sure we've reached the end of the file.
+    std::vector<char> buf(str.size() + 100);
+    int len = BIO_read(bio, buf.data(), static_cast<int>(buf.size()));
+    ASSERT_GT(len, 0);
+    EXPECT_EQ(Bytes(buf.data(), len), Bytes(str));
+  };
+  auto expect_binary_mode = [&](BIO *bio) {
+    expect_file_contents(bio, "hello\r\nworld");
+  };
+  auto expect_text_mode = [&](BIO *bio) {
+#if defined(OPENSSL_WINDOWS)
+    expect_file_contents(bio, "hello\nworld");
+#else
+    expect_file_contents(bio, "hello\r\nworld");
+#endif
+  };
+
+  // |BIO_read_filename| should open in binary mode.
   bssl::UniquePtr<BIO> bio(BIO_new(BIO_s_file()));
   ASSERT_TRUE(bio);
-  ASSERT_TRUE(BIO_read_filename(bio.get(), file.path().c_str()));
-  char buf[2];
-  ASSERT_EQ(2, BIO_read(bio.get(), buf, 2));
-  EXPECT_EQ(Bytes(buf, 2), Bytes("\r\n"));
+  ASSERT_TRUE(BIO_read_filename(bio.get(), temp.path().c_str()));
+  expect_binary_mode(bio.get());
+  // |BIO_new_file| does not set |BIO_FP_TEXT|, so expect it to set the file's
+  // mode to binary in all cases. This odd behavior, but it's what OpenSSL does.
+  bio.reset(BIO_new_file(temp.path().c_str(), "rb"));
+  ASSERT_TRUE(bio);
+  expect_binary_mode(bio.get());
+  bio.reset(BIO_new_file(temp.path().c_str(), "r"));
+  ASSERT_TRUE(bio);
+  // NOTE: Our behavior here aligns with OpenSSL which is to |_setmode| the file
+  // to binary. BoringSSL would |expect_text_mode| below because it respects 
+  // default mode on Windows which is text and doesn't call |_setmode| (unless
+  // |BIO_FP_TEXT| is set, which is not the case here).
+  expect_binary_mode(bio.get());
+  // |BIO_new_fp| will always set |_O_BINARY| if |BIO_FP_TEXT| is not set in the
+  // call to |BIO_new_fp|.
+  ScopedFILE file = temp.Open("rb");
+  ASSERT_TRUE(file);
+  bio.reset(BIO_new_fp(file.get(), BIO_NOCLOSE));
+  ASSERT_TRUE(bio);
+  expect_binary_mode(bio.get());
+  file = temp.Open("r");
+  ASSERT_TRUE(file);
+  bio.reset(BIO_new_fp(file.get(), BIO_NOCLOSE));
+  ASSERT_TRUE(bio);
+  // NOTE: Our behavior here aligns with OpenSSL. BoringSSL would
+  // |expect_text_mode| below because they don't call |_setmode| unless
+  // |BIO_FP_TEXT| is set.
+  expect_binary_mode(bio.get());
+  // However, |BIO_FP_TEXT| changes the file to be text mode, no matter how it
+  // was opened.
+  file = temp.Open("rb");
+  ASSERT_TRUE(file);
+  bio.reset(BIO_new_fp(file.get(), BIO_NOCLOSE | BIO_FP_TEXT));
+  ASSERT_TRUE(bio);
+  expect_text_mode(bio.get());
+  file = temp.Open("r");
+  ASSERT_TRUE(file);
+  bio.reset(BIO_new_fp(file.get(), BIO_NOCLOSE | BIO_FP_TEXT));
+  ASSERT_TRUE(bio);
+  expect_text_mode(bio.get());
+  // |BIO_new_fd| inherits the FD's existing mode.
+  ScopedFD fd = temp.OpenFD(kOpenReadOnlyBinary);
+  ASSERT_TRUE(fd.is_valid());
+  bio.reset(BIO_new_fd(fd.get(), BIO_NOCLOSE));
+  ASSERT_TRUE(bio);
+  expect_binary_mode(bio.get());
+  fd = temp.OpenFD(kOpenReadOnlyText);
+  ASSERT_TRUE(fd.is_valid());
+  bio.reset(BIO_new_fd(fd.get(), BIO_NOCLOSE));
+  ASSERT_TRUE(bio);
+  expect_text_mode(bio.get());
 }
 
 // Run through the tests twice, swapping |bio1| and |bio2|, for symmetry.
diff --git a/crypto/bio/file.c b/crypto/bio/file.c
index 91bdf1b81f..9a520f2a5e 100644
--- a/crypto/bio/file.c
+++ b/crypto/bio/file.c
@@ -206,9 +206,13 @@ static long file_ctrl(BIO *b, int cmd, long num, void *ptr) {
       b->init = 1;
 #if defined(OPENSSL_WINDOWS)
       // Windows differentiates between "text" and "binary" file modes, so set
-      // the file to text mode if caller specifies BIO_FP_TEXT flag.
+      // the file to text mode if caller specifies BIO_FP_TEXT flag. If
+      // |BIO_FP_TEXT| is not set, we still call |_setmode| with |_O_BINARY| to
+      // match OpenSSL's behavior. BoringSSL, on the other hand, does nothing in
+      // this case.
       //
       // https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/setmode?view=msvc-170#remarks
+      // https://github.com/google/boringssl/commit/5ee4e9512e9a99f97c4a3fad397034028b3457c2
       _setmode(_fileno(b->ptr), num & BIO_FP_TEXT ? _O_TEXT : _O_BINARY);
 #endif
       break;
@@ -299,8 +303,8 @@ int BIO_get_fp(BIO *bio, FILE **out_file) {
   return (int)BIO_ctrl(bio, BIO_C_GET_FILE_PTR, 0, (char *)out_file);
 }
 
-int BIO_set_fp(BIO *bio, FILE *file, int close_flag) {
-  return (int)BIO_ctrl(bio, BIO_C_SET_FILE_PTR, close_flag, (char *)file);
+int BIO_set_fp(BIO *bio, FILE *file, int flags) {
+  return (int)BIO_ctrl(bio, BIO_C_SET_FILE_PTR, flags, (char *)file);
 }
 
 int BIO_read_filename(BIO *bio, const char *filename) {