diff --git a/iocore/net/ProxyProtocol.h b/iocore/net/ProxyProtocol.h
index 607dcdfbd30..f5961af4e6a 100644
--- a/iocore/net/ProxyProtocol.h
+++ b/iocore/net/ProxyProtocol.h
@@ -23,8 +23,7 @@
   limitations under the License.
  */
 
-#ifndef ProxyProtocol_H_
-#define ProxyProtocol_H_
+#pragma once
 
 #include "tscore/ink_defs.h"
 #include "tscore/ink_memory.h"
@@ -51,5 +50,3 @@ const size_t PROXY_V2_CONNECTION_HEADER_LEN_MIN = 16;
 
 const size_t PROXY_V1_CONNECTION_HEADER_LEN_MAX = 108;
 const size_t PROXY_V2_CONNECTION_HEADER_LEN_MAX = 16;
-
-#endif /* ProxyProtocol_H_ */
diff --git a/plugins/experimental/cookie_remap/cookiejar.h b/plugins/experimental/cookie_remap/cookiejar.h
index 34e9907317b..25475817f2e 100644
--- a/plugins/experimental/cookie_remap/cookiejar.h
+++ b/plugins/experimental/cookie_remap/cookiejar.h
@@ -16,8 +16,7 @@
   limitations under the License.
 */
 
-#ifndef CKREMAP_COOKIEJAR_H_
-#define CKREMAP_COOKIEJAR_H_
+#pragma once
 
 #include <string>
 #include <unordered_map>
@@ -58,5 +57,3 @@ class CookieJar
 
   unordered_map<string, CookieVal> m_jar;
 };
-
-#endif // CKREMAP_COOKIEJAR_H_
diff --git a/plugins/experimental/cookie_remap/hash.h b/plugins/experimental/cookie_remap/hash.h
index 6d6c94131bb..18375b3ecb9 100644
--- a/plugins/experimental/cookie_remap/hash.h
+++ b/plugins/experimental/cookie_remap/hash.h
@@ -16,8 +16,7 @@
   limitations under the License.
 */
 
-#ifndef _CKREMAP_HASH_H_
-#define _CKREMAP_HASH_H_
+#pragma once
 
 #include <stddef.h> // NOLINT(modernize-deprecated-headers)
 #include <sys/types.h>
@@ -50,5 +49,3 @@ uint32_t hash_fnv32_buckets(const char *buf, size_t len, uint32_t num_buckets);
 #ifdef __cplusplus
 }
 #endif
-
-#endif /* _CKREMAP_HASH_H_ */
diff --git a/plugins/experimental/cookie_remap/strip.h b/plugins/experimental/cookie_remap/strip.h
index 5a6e97c3551..67af1d08f13 100644
--- a/plugins/experimental/cookie_remap/strip.h
+++ b/plugins/experimental/cookie_remap/strip.h
@@ -16,8 +16,7 @@
   limitations under the License.
 */
 
-#ifndef CKREMAP_IV_H
-#define CKREMAP_IV_H
+#pragma once
 
 #include <sys/types.h>
 
@@ -142,5 +141,3 @@ int get_stripped(const char *in, ssize_t in_len, char *out, int *out_len, unsign
 #ifdef __cplusplus
 }
 #endif
-
-#endif /* CKREMAP_IV_H */
diff --git a/plugins/experimental/maxmind_acl/mmdb.h b/plugins/experimental/maxmind_acl/mmdb.h
index 828ffe3bff9..2e31c56498f 100644
--- a/plugins/experimental/maxmind_acl/mmdb.h
+++ b/plugins/experimental/maxmind_acl/mmdb.h
@@ -16,7 +16,7 @@
   limitations under the License.
 */
 
-//#pragma once
+#pragma once
 
 #include <cstdio>
 #include <cstring>
diff --git a/plugins/experimental/memcache/tsmemcache.h b/plugins/experimental/memcache/tsmemcache.h
index fc6c81188a5..5c591ca1ff3 100644
--- a/plugins/experimental/memcache/tsmemcache.h
+++ b/plugins/experimental/memcache/tsmemcache.h
@@ -21,9 +21,6 @@
   limitations under the License.
  */
 
-#ifndef tsmemcache_h
-#define tsmemcache_h
-
 #include "I_EventSystem.h"
 #include "I_Net.h"
 #include "I_Cache.h"
@@ -241,5 +238,3 @@ xatoull(char *s, char *e)
   }
   return n;
 }
-
-#endif
diff --git a/proxy/http3/Http3SessionAccept.h b/proxy/http3/Http3SessionAccept.h
index 8bb388e3daf..5c872261a37 100644
--- a/proxy/http3/Http3SessionAccept.h
+++ b/proxy/http3/Http3SessionAccept.h
@@ -21,8 +21,7 @@
   limitations under the License.
  */
 
-#ifndef __HTTP_QUIC_SESSION_ACCEPT_H__
-#define __HTTP_QUIC_SESSION_ACCEPT_H__
+#pragma once
 
 #include "tscore/ink_platform.h"
 #include "I_Net.h"
@@ -53,5 +52,3 @@ class Http3SessionAccept : public SessionAccept
 
   HttpSessionAccept::Options options;
 };
-
-#endif // __HTTP_QUIC_SESSION_ACCEPT_H__