diff --git a/tensorflow_text/core/kernels/whitespace_tokenizer.h b/tensorflow_text/core/kernels/whitespace_tokenizer.h
index cc2d92b53..d249fda88 100644
--- a/tensorflow_text/core/kernels/whitespace_tokenizer.h
+++ b/tensorflow_text/core/kernels/whitespace_tokenizer.h
@@ -45,7 +45,8 @@ class WhitespaceTokenizerConfig {
       : config_(*config), max_codepoint_(config->length() * 8) {}
 
   inline bool IsWhitespace(const UChar32 codepoint) const {
-    return codepoint <= max_codepoint_ &&
+    return codepoint != U_SENTINEL &&
+           codepoint < max_codepoint_ &&
            config_[codepoint >> 3] & (1 << (char)(codepoint & 0x7));
   }
 
diff --git a/tensorflow_text/core/kernels/whitespace_tokenizer_test.cc b/tensorflow_text/core/kernels/whitespace_tokenizer_test.cc
index 84b6d5047..8f2519d54 100644
--- a/tensorflow_text/core/kernels/whitespace_tokenizer_test.cc
+++ b/tensorflow_text/core/kernels/whitespace_tokenizer_test.cc
@@ -62,6 +62,18 @@ TEST(WhitespaceTokenizerTest, Internationalization) {
   EXPECT_THAT(output_end_offsets, ElementsAre(5, 10, 15));
 }
 
+TEST(WhitespaceTokenizerTest, InvalidCodepoint) {
+  absl::string_view input("\xE3");
+  std::vector<std::string> output_tokens;
+  std::vector<int> output_start_offsets;
+  std::vector<int> output_end_offsets;
+  std::string config = BuildWhitespaceTokenizerConfig();
+  WhitespaceTokenizer t(&config);
+  t.Tokenize(input, &output_tokens, &output_start_offsets, &output_end_offsets);
+  EXPECT_THAT(output_start_offsets, ElementsAre(0));
+  EXPECT_THAT(output_end_offsets, ElementsAre(1));
+}
+
 }  // namespace
 }  // namespace text
 }  // namespace tensorflow