diff --git a/security/pkix/include/pkix/Input.h b/security/pkix/include/pkix/Input.h
index 77eeae9bd6c..dc0c04b69a2 100644
--- a/security/pkix/include/pkix/Input.h
+++ b/security/pkix/include/pkix/Input.h
@@ -22,8 +22,8 @@
  * limitations under the License.
  */
 
-#ifndef mozilla_pkix__Input_h
-#define mozilla_pkix__Input_h
+#ifndef mozilla_pkix_Input_h
+#define mozilla_pkix_Input_h
 
 #include <cstring>
 
@@ -341,4 +341,4 @@ InputContains(const Input& input, uint8_t toFind)
 
 } } // namespace mozilla::pkix
 
-#endif // mozilla_pkix__Input_h
+#endif // mozilla_pkix_Input_h
diff --git a/security/pkix/include/pkix/Result.h b/security/pkix/include/pkix/Result.h
index 13d71071af5..97f5b3f121f 100644
--- a/security/pkix/include/pkix/Result.h
+++ b/security/pkix/include/pkix/Result.h
@@ -22,8 +22,8 @@
  * limitations under the License.
  */
 
-#ifndef mozilla_pkix__Result_h
-#define mozilla_pkix__Result_h
+#ifndef mozilla_pkix_Result_h
+#define mozilla_pkix_Result_h
 
 #include <cassert>
 
@@ -218,4 +218,4 @@ NotReached(const char* /*explanation*/, Result result)
 
 } } // namespace mozilla::pkix
 
-#endif // mozilla_pkix__Result_h
+#endif // mozilla_pkix_Result_h
diff --git a/security/pkix/include/pkix/ScopedPtr.h b/security/pkix/include/pkix/ScopedPtr.h
index a0835588868..238de61e3da 100644
--- a/security/pkix/include/pkix/ScopedPtr.h
+++ b/security/pkix/include/pkix/ScopedPtr.h
@@ -22,8 +22,8 @@
  * limitations under the License.
  */
 
-#ifndef mozilla_pkix__ScopedPtr_h
-#define mozilla_pkix__ScopedPtr_h
+#ifndef mozilla_pkix_ScopedPtr_h
+#define mozilla_pkix_ScopedPtr_h
 
 #include "pkix/stdkeywords.h"
 
@@ -103,4 +103,4 @@ operator!=(const ScopedPtr<T, Destroyer>& a, T* b)
 
 } } // namespace mozilla::pkix
 
-#endif // mozilla_pkix__ScopedPtr_h
+#endif // mozilla_pkix_ScopedPtr_h
diff --git a/security/pkix/include/pkix/Time.h b/security/pkix/include/pkix/Time.h
index f74ab2dfb53..5365bd3e370 100644
--- a/security/pkix/include/pkix/Time.h
+++ b/security/pkix/include/pkix/Time.h
@@ -22,8 +22,8 @@
  * limitations under the License.
  */
 
-#ifndef mozilla_pkix__Time_h
-#define mozilla_pkix__Time_h
+#ifndef mozilla_pkix_Time_h
+#define mozilla_pkix_Time_h
 
 #include <ctime>
 #include <limits>
@@ -124,4 +124,4 @@ Time TimeFromEpochInSeconds(uint64_t secondsSinceEpoch);
 
 } } // namespace mozilla::pkix
 
-#endif // mozilla_pkix__Time_h
+#endif // mozilla_pkix_Time_h
diff --git a/security/pkix/include/pkix/pkix.h b/security/pkix/include/pkix/pkix.h
index 6a3b1e2f788..72fedb94c8b 100644
--- a/security/pkix/include/pkix/pkix.h
+++ b/security/pkix/include/pkix/pkix.h
@@ -22,8 +22,8 @@
  * limitations under the License.
  */
 
-#ifndef mozilla_pkix__pkix_h
-#define mozilla_pkix__pkix_h
+#ifndef mozilla_pkix_pkix_h
+#define mozilla_pkix_pkix_h
 
 #include "pkixtypes.h"
 
@@ -149,4 +149,4 @@ Result VerifyEncodedOCSPResponse(TrustDomain& trustDomain,
 
 } } // namespace mozilla::pkix
 
-#endif // mozilla_pkix__pkix_h
+#endif // mozilla_pkix_pkix_h
diff --git a/security/pkix/include/pkix/pkixnss.h b/security/pkix/include/pkix/pkixnss.h
index a7bb1fa2fff..33d5fe022cb 100644
--- a/security/pkix/include/pkix/pkixnss.h
+++ b/security/pkix/include/pkix/pkixnss.h
@@ -22,8 +22,8 @@
  * limitations under the License.
  */
 
-#ifndef mozilla_pkix__pkixnss_h
-#define mozilla_pkix__pkixnss_h
+#ifndef mozilla_pkix_pkixnss_h
+#define mozilla_pkix_pkixnss_h
 
 #include "pkixtypes.h"
 #include "prerror.h"
@@ -95,4 +95,4 @@ inline SECItem UnsafeMapInputToSECItem(Input input)
 
 } } // namespace mozilla::pkix
 
-#endif // mozilla_pkix__pkixnss_h
+#endif // mozilla_pkix_pkixnss_h
diff --git a/security/pkix/include/pkix/pkixtypes.h b/security/pkix/include/pkix/pkixtypes.h
index 00da6d9933f..d70d414f884 100644
--- a/security/pkix/include/pkix/pkixtypes.h
+++ b/security/pkix/include/pkix/pkixtypes.h
@@ -22,8 +22,8 @@
  * limitations under the License.
  */
 
-#ifndef mozilla_pkix__pkixtypes_h
-#define mozilla_pkix__pkixtypes_h
+#ifndef mozilla_pkix_pkixtypes_h
+#define mozilla_pkix_pkixtypes_h
 
 #include "pkix/Input.h"
 #include "pkix/Time.h"
@@ -342,4 +342,4 @@ protected:
 
 } } // namespace mozilla::pkix
 
-#endif // mozilla_pkix__pkixtypes_h
+#endif // mozilla_pkix_pkixtypes_h
diff --git a/security/pkix/include/pkix/stdkeywords.h b/security/pkix/include/pkix/stdkeywords.h
index b5071caa0f8..655fcf3695a 100644
--- a/security/pkix/include/pkix/stdkeywords.h
+++ b/security/pkix/include/pkix/stdkeywords.h
@@ -22,8 +22,8 @@
  * limitations under the License.
  */
 
-#ifndef mozilla_pkix__stdkeywords_h
-#define mozilla_pkix__stdkeywords_h
+#ifndef mozilla_pkix_stdkeywords_h
+#define mozilla_pkix_stdkeywords_h
 
 #if defined(__GNUC__) && !defined(__clang__)
 
@@ -35,4 +35,4 @@
 
 #endif // defined(__GNUC__) && !defined(__clang__)
 
-#endif // mozilla_pkix__stdkeywords_h
+#endif // mozilla_pkix_stdkeywords_h
diff --git a/security/pkix/lib/pkixcheck.h b/security/pkix/lib/pkixcheck.h
index 52af85f127d..b069a1a1f44 100644
--- a/security/pkix/lib/pkixcheck.h
+++ b/security/pkix/lib/pkixcheck.h
@@ -22,8 +22,8 @@
  * limitations under the License.
  */
 
-#ifndef mozilla_pkix__pkixcheck_h
-#define mozilla_pkix__pkixcheck_h
+#ifndef mozilla_pkix_pkixcheck_h
+#define mozilla_pkix_pkixcheck_h
 
 #include "pkix/pkixtypes.h"
 
@@ -47,4 +47,4 @@ Result CheckNameConstraints(Input encodedNameConstraints,
 
 } } // namespace mozilla::pkix
 
-#endif // mozilla_pkix__pkixcheck_h
+#endif // mozilla_pkix_pkixcheck_h
diff --git a/security/pkix/lib/pkixder.h b/security/pkix/lib/pkixder.h
index 4ca48559ec0..2f6276c614e 100644
--- a/security/pkix/lib/pkixder.h
+++ b/security/pkix/lib/pkixder.h
@@ -22,8 +22,8 @@
  * limitations under the License.
  */
 
-#ifndef mozilla_pkix__pkixder_h
-#define mozilla_pkix__pkixder_h
+#ifndef mozilla_pkix_pkixder_h
+#define mozilla_pkix_pkixder_h
 
 // Expect* functions advance the input mark and return Success if the input
 // matches the given criteria; they fail with the input mark in an undefined
@@ -631,4 +631,4 @@ Result SignedData(Reader& input, /*out*/ Reader& tbs,
 
 } } } // namespace mozilla::pkix::der
 
-#endif // mozilla_pkix__pkixder_h
+#endif // mozilla_pkix_pkixder_h
diff --git a/security/pkix/lib/pkixutil.h b/security/pkix/lib/pkixutil.h
index eac104dc0f7..165d9a6b208 100644
--- a/security/pkix/lib/pkixutil.h
+++ b/security/pkix/lib/pkixutil.h
@@ -22,8 +22,8 @@
  * limitations under the License.
  */
 
-#ifndef mozilla_pkix__pkixutil_h
-#define mozilla_pkix__pkixutil_h
+#ifndef mozilla_pkix_pkixutil_h
+#define mozilla_pkix_pkixutil_h
 
 #include "pkixder.h"
 
@@ -254,4 +254,4 @@ WrappedVerifySignedData(TrustDomain& trustDomain,
 
 } } // namespace mozilla::pkix
 
-#endif // mozilla_pkix__pkixutil_h
+#endif // mozilla_pkix_pkixutil_h
diff --git a/security/pkix/test/gtest/pkixgtest.h b/security/pkix/test/gtest/pkixgtest.h
index 5f7b2657cfd..5e303b0baae 100644
--- a/security/pkix/test/gtest/pkixgtest.h
+++ b/security/pkix/test/gtest/pkixgtest.h
@@ -21,8 +21,8 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-#ifndef mozilla_pkix__pkixgtest_h
-#define mozilla_pkix__pkixgtest_h
+#ifndef mozilla_pkix_pkixgtest_h
+#define mozilla_pkix_pkixgtest_h
 
 #include <ostream>
 
@@ -53,4 +53,4 @@ extern const std::time_t oneDayAfterNow;
 
 } } } // namespace mozilla::pkix::test
 
-#endif // mozilla_pkix__pkixgtest_h
+#endif // mozilla_pkix_pkixgtest_h
diff --git a/security/pkix/test/lib/pkixtestutil.h b/security/pkix/test/lib/pkixtestutil.h
index 4eaa9d3a481..e579e5bc3c8 100644
--- a/security/pkix/test/lib/pkixtestutil.h
+++ b/security/pkix/test/lib/pkixtestutil.h
@@ -22,8 +22,8 @@
  * limitations under the License.
  */
 
-#ifndef mozilla_pkix_test__pkixtestutils_h
-#define mozilla_pkix_test__pkixtestutils_h
+#ifndef mozilla_pkix_test_pkixtestutils_h
+#define mozilla_pkix_test_pkixtestutils_h
 
 #include <ctime>
 #include <stdint.h> // Some Mozilla-supported compilers lack <cstdint>
@@ -371,4 +371,4 @@ ByteString CreateEncodedOCSPResponse(OCSPResponseContext& context);
 
 } } } // namespace mozilla::pkix::test
 
-#endif // mozilla_pkix_test__pkixtestutils_h
+#endif // mozilla_pkix_test_pkixtestutils_h