diff --git a/onnxruntime/contrib_ops/cpu/tokenizer.cc b/onnxruntime/contrib_ops/cpu/tokenizer.cc
index 36c99909c5..404b395c96 100644
--- a/onnxruntime/contrib_ops/cpu/tokenizer.cc
+++ b/onnxruntime/contrib_ops/cpu/tokenizer.cc
@@ -277,7 +277,6 @@ Tokenizer::Tokenizer(const OpKernelInfo& info) : OpKernel(info) {
       // Use tokenexp
       re2::RE2::Options options;
       options.set_longest_match(true);
-      options.set_posix_syntax(true);
       std::unique_ptr<re2::RE2> regex(new re2::RE2(tokenexp, options));
       if (!regex->ok()) {
         ORT_THROW("Can not digest regex: ", regex->error());
diff --git a/onnxruntime/test/contrib_ops/tokenizer_test.cc b/onnxruntime/test/contrib_ops/tokenizer_test.cc
index 8823b53eb2..0375b0f76e 100644
--- a/onnxruntime/test/contrib_ops/tokenizer_test.cc
+++ b/onnxruntime/test/contrib_ops/tokenizer_test.cc
@@ -809,5 +809,26 @@ TEST(ContribOpTest, TokenizerExpression_RegDot) {
   test.Run(OpTester::ExpectResult::kExpectSuccess);
 }
 
+TEST(ContribOpTest, TokenizerExpression_RegChar) {
+  OpTester test("Tokenizer", opset_ver, domain);
+  const std::string tokenexp(u8"\\w");
+  InitTestAttr(test, true, {}, 1, tokenexp);
+
+  std::vector<int64_t> dims{1};
+  std::vector<std::string> input{u8"a;;;b"};
+  test.AddInput<std::string>("T", dims, input);
+
+  std::vector<int64_t> output_dims(dims);
+  output_dims.push_back(int64_t(4));
+  std::vector<std::string> output{
+      start_mark,
+      u8"a",
+      u8"b",
+      end_mark};
+
+  test.AddOutput<std::string>("Y", output_dims, output);
+  test.Run(OpTester::ExpectResult::kExpectSuccess);
+}
+
 }  // namespace test
 }  // namespace onnxruntime