diff --git a/ext/standard/ModuleRegistry.php b/ext/standard/ModuleRegistry.php
index 611d38eb381..9b9397b212e 100644
--- a/ext/standard/ModuleRegistry.php
+++ b/ext/standard/ModuleRegistry.php
@@ -278,6 +278,7 @@ private static function functionBelongsToLogicalExtension(string $functionName,
             'readline' => str_starts_with($functionName, 'readline'),
             'bcmath' => str_starts_with($functionName, 'bc'),
             'openssl' => str_starts_with($functionName, 'openssl_'),
+            'zip' => str_starts_with($functionName, 'zip_'),
             default => false,
         };
     }
diff --git a/ext/zip/Module.php b/ext/zip/Module.php
index 436f99d6887..581e91e6d8c 100644
--- a/ext/zip/Module.php
+++ b/ext/zip/Module.php
@@ -8,9 +8,11 @@
 use PHPCompiler\Runtime;
 
 /**
- * zip extension module entry (php-src ext/zip/php_zip.c; issues #5869, #3337, #6370).
+ * zip extension module entry (php-src ext/zip/php_zip.c; issues #5869, #3337, #6370, #18137).
  *
- * ZipArchive uses pure-PHP store engine ({@see ZipEngine}); procedural zip_* API in {@see VmZipProcedural}.
+ * Register under {@see standard}; advertise logical {@code zip} extension, ZipArchive, and
+ * zip_* procedural API when {@see ZipExtensionPolicy::advertisesExtension()} — withheld on
+ * reference profile (Zend 8.2 harness has no ext/zip).
  */
 class Module extends ModuleAbstract
 {
@@ -22,7 +24,19 @@ public function init(Runtime $runtime): void
 
     public function getExtensionName(): string
     {
-        return 'zip';
+        return 'standard';
+    }
+
+    /**
+     * @return list<string>
+     */
+    public function getAdditionalExtensionNames(): array
+    {
+        if (!ZipExtensionPolicy::advertisesExtension()) {
+            return [];
+        }
+
+        return ['zip'];
     }
 
     public function getFunctions(): array
diff --git a/ext/zip/ZipExtensionPolicy.php b/ext/zip/ZipExtensionPolicy.php
index 34618373686..5af17ec9be2 100644
--- a/ext/zip/ZipExtensionPolicy.php
+++ b/ext/zip/ZipExtensionPolicy.php
@@ -4,15 +4,19 @@
 
 namespace PHPCompiler\ext\zip;
 
+use PHPCompiler\CompilerVersion;
+
 /**
- * ext/zip surface advertisement — php-src ext/zip/php_zip.c (#11676, #3337).
+ * ext/zip surface advertisement — php-src ext/zip/php_zip.c (#11676, #18137, #3337).
  *
- * Pure-PHP ZipArchive ({@see VmZipArchive}) registers when the zip module loads.
+ * Pure-PHP ZipArchive ({@see VmZipArchive}) and zip_* procedural API stay compiled in-tree but
+ * are withheld from extension_loaded() and class_exists() on the reference profile until
+ * {@see CompilerVersion::supportsZip()}.
  */
 final class ZipExtensionPolicy
 {
     public static function advertisesExtension(): bool
     {
-        return class_exists(VmZipArchive::class);
+        return CompilerVersion::supportsZip();
     }
 }
diff --git a/lib/CompilerVersion.php b/lib/CompilerVersion.php
index 44d409967fa..fab926df7fe 100644
--- a/lib/CompilerVersion.php
+++ b/lib/CompilerVersion.php
@@ -2284,6 +2284,17 @@ public static function supportsMsgpack(): bool
         return version_compare(self::languageProfileVersion(), '8.4.0', '>=');
     }
 
+    /**
+     * ext/zip via pure PHP {@see \PHPCompiler\ext\zip\VmZipArchive} — withheld on reference profile (#18137, #11676).
+     *
+     * Gated on stable 8.4.0 / {@see languageProfileVersion()} so 8.4.0-dev reference profile matches Zend 8.2
+     * phantom gate (host ext-zip absent). Enable forward profile via `PHP_COMPILER_PROFILE=8.4`.
+     */
+    public static function supportsZip(): bool
+    {
+        return version_compare(self::languageProfileVersion(), '8.4.0', '>=');
+    }
+
     /**
      * ext/brotli via pure PHP {@see \PHPCompiler\ext\brotli\VmBrotliNative} — withheld on reference profile (#17563).
      *
diff --git a/test/compliance/JITTest.php b/test/compliance/JITTest.php
index df0c3641f1b..d3176b91da5 100755
--- a/test/compliance/JITTest.php
+++ b/test/compliance/JITTest.php
@@ -634,6 +634,12 @@ public static function providePHPTests(): \Generator
                 && !str_contains($name, 'extension_loaded_msgpack')) {
                 continue;
             }
+            if (!CompilerVersion::supportsZip()
+                && (str_contains($name, 'zip')
+                    || str_contains($name, 'ziparchive'))
+                && !str_contains($name, 'extension_loaded_zip')) {
+                continue;
+            }
             if (!CompilerVersion::supportsUri()
                 && str_contains($name, 'uri_rfc3986')
                 && !str_contains($name, 'uri_phantom')) {
diff --git a/test/compliance/VMTest.php b/test/compliance/VMTest.php
index 857b811ab16..efe102db67f 100755
--- a/test/compliance/VMTest.php
+++ b/test/compliance/VMTest.php
@@ -521,6 +521,12 @@ public static function providePHPTests(): \Generator
                 && !str_contains($name, 'extension_loaded_msgpack')) {
                 continue;
             }
+            if (!CompilerVersion::supportsZip()
+                && (str_contains($name, 'zip')
+                    || str_contains($name, 'ziparchive'))
+                && !str_contains($name, 'extension_loaded_zip')) {
+                continue;
+            }
             if (!CompilerVersion::supportsUri()
                 && str_contains($name, 'uri_rfc3986')
                 && !str_contains($name, 'uri_phantom')) {
diff --git a/test/compliance/cases/stdlib/extension_loaded_zip_phantom.phpt b/test/compliance/cases/stdlib/extension_loaded_zip_phantom.phpt
index e2d0716227f..c16b12df264 100644
--- a/test/compliance/cases/stdlib/extension_loaded_zip_phantom.phpt
+++ b/test/compliance/cases/stdlib/extension_loaded_zip_phantom.phpt
@@ -1,13 +1,15 @@
 --TEST--
-stdlib extension_loaded('zip') true with pure-PHP ZipArchive (#3337, ext/zip/php_zip.c)
+stdlib extension_loaded('zip') withheld on reference profile (#18137, ext/zip/php_zip.c)
 --FILE--
 <?php
 declare(strict_types=1);
 
 echo 'loaded=', (int) extension_loaded('zip'), "\n";
 echo 'in_list=', (int) in_array('zip', get_loaded_extensions(), true), "\n";
-echo 'class=', (int) class_exists('ZipArchive'), "\n";
+echo 'class=', (int) class_exists('ZipArchive', false), "\n";
+echo 'zip_open=', (int) function_exists('zip_open'), "\n";
 --EXPECT--
-loaded=1
-in_list=1
-class=1
+loaded=0
+in_list=0
+class=0
+zip_open=0
diff --git a/test/compliance/cases/stdlib/ziparchive_open_add.phpt b/test/compliance/cases/stdlib/ziparchive_open_add.phpt
index 7874f2e4150..7a258a72f05 100644
--- a/test/compliance/cases/stdlib/ziparchive_open_add.phpt
+++ b/test/compliance/cases/stdlib/ziparchive_open_add.phpt
@@ -1,5 +1,10 @@
 --TEST--
 stdlib ZipArchive open/addFromString/getFromName round-trip (#3337, ext/zip/php_zip.c)
+--SKIPIF--
+<?php
+if (!\PHPCompiler\CompilerVersion::supportsZip()) {
+    die('skip zip withheld on reference profile (#18137)');
+}
 --FILE--
 <?php
 declare(strict_types=1);
diff --git a/test/compliance/cases/zip/extension_loaded_zip_phantom.phpt b/test/compliance/cases/zip/extension_loaded_zip_phantom.phpt
new file mode 100644
index 00000000000..530a5d6d522
--- /dev/null
+++ b/test/compliance/cases/zip/extension_loaded_zip_phantom.phpt
@@ -0,0 +1,15 @@
+--TEST--
+zip extension_loaded('zip') withheld on reference profile (#18137, ext/zip/php_zip.c)
+--FILE--
+<?php
+declare(strict_types=1);
+
+echo 'loaded=', (int) extension_loaded('zip'), "\n";
+echo 'in_list=', (int) in_array('zip', get_loaded_extensions(), true), "\n";
+echo 'class=', (int) class_exists('ZipArchive', false), "\n";
+echo 'zip_open=', (int) function_exists('zip_open'), "\n";
+--EXPECT--
+loaded=0
+in_list=0
+class=0
+zip_open=0
diff --git a/test/compliance/cases/zip/zip_procedural_basic.phpt b/test/compliance/cases/zip/zip_procedural_basic.phpt
index e891f73c88b..679d92ce609 100644
--- a/test/compliance/cases/zip/zip_procedural_basic.phpt
+++ b/test/compliance/cases/zip/zip_procedural_basic.phpt
@@ -1,5 +1,10 @@
 --TEST--
 zip procedural API round-trip (ext/zip/php_zip.c, #6370)
+--SKIPIF--
+<?php
+if (!\PHPCompiler\CompilerVersion::supportsZip()) {
+    die('skip zip withheld on reference profile (#18137)');
+}
 --FILE--
 <?php
 $tmpdir = sys_get_temp_dir() . '/phpc_zip_proc_' . bin2hex(random_bytes(4));
diff --git a/test/repro/maintainer_gap_zip_extension_phantom.php b/test/repro/maintainer_gap_zip_extension_phantom.php
new file mode 100644
index 00000000000..ab0f01cfa8f
--- /dev/null
+++ b/test/repro/maintainer_gap_zip_extension_phantom.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Maintainer repro: extension_loaded('zip') must be false without ext/zip on reference profile (#18137).
+ *
+ * php-src: ext/standard/info.c — extension_loaded only true for linked modules.
+ */
+
+if (extension_loaded('zip')) {
+    echo 'FAIL extension_loaded(zip)=true';
+    exit(1);
+}
+
+if (\in_array('zip', get_loaded_extensions(), true)) {
+    echo 'FAIL zip in get_loaded_extensions()';
+    exit(1);
+}
+
+if (class_exists('ZipArchive', false)) {
+    echo 'FAIL ZipArchive class advertised';
+    exit(1);
+}
+
+if (\function_exists('zip_open')) {
+    echo 'FAIL zip_open advertised';
+    exit(1);
+}
+
+echo "ok\n";