diff --git a/docs/bootstrap-inventory.md b/docs/bootstrap-inventory.md
index a43a3526..36348c2b 100644
--- a/docs/bootstrap-inventory.md
+++ b/docs/bootstrap-inventory.md
@@ -8,9 +8,9 @@ Regenerate: `php script/bootstrap-inventory.php`
 
 | Metric | Count |
 |--------|------:|
-| PHP files on vm.php path | 239 |
+| PHP files on vm.php path | 240 |
 | Source constructs flagged (blockers) | 10 |
-| Source constructs flagged (warnings) | 628 |
+| Source constructs flagged (warnings) | 629 |
 
 ## Compiler CFG gaps (`lib/Compiler.php`)
 
@@ -37,6 +37,7 @@ These `LogicException` messages indicate CFG ops or expressions not yet lowered:
 | `ext/standard/JitDate.php` | 0 | 1 |
 | `ext/standard/JitEnv.php` | 0 | 1 |
 | `ext/standard/JitExplode.php` | 0 | 1 |
+| `ext/standard/JitGetallheaders.php` | 0 | 1 |
 | `ext/standard/JitHeader.php` | 0 | 1 |
 | `ext/standard/JitHex2bin.php` | 0 | 1 |
 | `ext/standard/JitHtmlspecialchars.php` | 0 | 1 |
@@ -292,6 +293,11 @@ These `LogicException` messages indicate CFG ops or expressions not yet lowered:
 **Warnings** (review for bootstrap subset):
 - 1 class method(s) — PHPCfg Op\Stmt\ClassMethod not lowered in Compiler
 
+### `ext/standard/JitGetallheaders.php`
+
+**Warnings** (review for bootstrap subset):
+- 1 class method(s) — PHPCfg Op\Stmt\ClassMethod not lowered in Compiler
+
 ### `ext/standard/JitHeader.php`
 
 **Warnings** (review for bootstrap subset):
@@ -1301,10 +1307,10 @@ These `LogicException` messages indicate CFG ops or expressions not yet lowered:
 - new JIT\Call\Native (line 149)
 - new ext\standard\boolval (line 268)
 - new Variable (line 432)
-- new Variable (line 813)
-- new Operand\Literal (line 883)
-- new Operand\Literal (line 887)
+- new Variable (line 821)
 - new Operand\Literal (line 891)
+- new Operand\Literal (line 895)
+- new Operand\Literal (line 899)
 - 12 class method(s) — PHPCfg Op\Stmt\ClassMethod not lowered in Compiler
 
 ### `lib/JIT/Analyzer.php`
diff --git a/docs/bootstrap-profile.json b/docs/bootstrap-profile.json
index 1234852c..791ec03a 100644
--- a/docs/bootstrap-profile.json
+++ b/docs/bootstrap-profile.json
@@ -35,6 +35,7 @@
         "ext/standard/JitDate.php",
         "ext/standard/JitEnv.php",
         "ext/standard/JitExplode.php",
+        "ext/standard/JitGetallheaders.php",
         "ext/standard/JitHeader.php",
         "ext/standard/JitHex2bin.php",
         "ext/standard/JitHtmlspecialchars.php",
@@ -273,9 +274,9 @@
         "test/bootstrap-aot/echo_hello.php"
     ],
     "totals": {
-        "inventory_files": 239,
+        "inventory_files": 240,
         "excluded": 2,
-        "eligible": 237,
+        "eligible": 238,
         "aot_lint_targets": 2
     }
 }
diff --git a/docs/capabilities.md b/docs/capabilities.md
index 36cce544..782c0597 100644
--- a/docs/capabilities.md
+++ b/docs/capabilities.md
@@ -8,7 +8,7 @@ Auto-generated by `script/capability-matrix.php`. Do not edit by hand.
 | `array_combine` | yes | no | no | standard | doc: VM only; not implemented for JIT in this compiler build |
 | `array_fill` | yes | yes | yes | standard | JIT PHPT |
 | `array_flip` | yes | no | no | standard | doc: VM only; not implemented for JIT in this compiler build |
-| `array_key_exists` | yes | yes | yes | standard | AOT PHPT |
+| `array_key_exists` | yes | yes | yes | standard | JIT PHPT; AOT PHPT |
 | `array_keys` | yes | yes | yes | standard | doc: VM only |
 | `array_merge` | yes | yes | yes | standard | doc: VM only |
 | `array_pop` | yes | yes | yes | standard | JIT PHPT; AOT PHPT |
@@ -42,7 +42,7 @@ Auto-generated by `script/capability-matrix.php`. Do not edit by hand.
 | `floatval` | yes | yes | yes | standard |  |
 | `floor` | yes | yes | yes | standard |  |
 | `fmod` | yes | yes | yes | standard |  |
-| `getallheaders` | yes | no | no | standard | doc: VM only; not implemented for JIT in this compiler build |
+| `getallheaders` | yes | yes | yes | standard | JIT PHPT; AOT PHPT |
 | `getenv` | yes | yes | yes | standard | JIT PHPT; AOT PHPT |
 | `gettype` | yes | yes | yes | standard |  |
 | `glob` | yes | yes | yes | standard |  |
diff --git a/ext/standard/JitGetallheaders.php b/ext/standard/JitGetallheaders.php
new file mode 100644
index 00000000..ad57266a
--- /dev/null
+++ b/ext/standard/JitGetallheaders.php
@@ -0,0 +1,75 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PHPCompiler\ext\standard;
+
+use PHPCompiler\JIT\Context;
+use PHPCompiler\JIT\HashTableHelper;
+use PHPCompiler\JIT\SuperglobalInit;
+use PHPCompiler\JIT\Variable as JITVariable;
+use PHPCompiler\VM\HashTable;
+use PHPCompiler\VM\Variable as VMVariable;
+use PHPCompiler\Web\Superglobals;
+use PHPLLVM\Value;
+
+/**
+ * LLVM JIT/AOT helper for getallheaders() — copy HTTP_* / CONTENT_* from sg_SERVER.
+ */
+final class JitGetallheaders
+{
+    public static function invoke(Context $context): Value
+    {
+        $result = HashTableHelper::alloc($context);
+        $serverVar = SuperglobalInit::load($context, '_SERVER');
+        $serverPtr = $context->helper->loadValue($serverVar);
+
+        $vmServer = $context->runtime->vmContext->getSuperglobal('_SERVER');
+        if (null === $vmServer || VMVariable::TYPE_ARRAY !== $vmServer->type) {
+            return $result;
+        }
+        $table = $vmServer->toArray();
+        if (!$table instanceof HashTable) {
+            return $result;
+        }
+
+        foreach ($table->iterateKeyed(true) as [$keyVar, $valueVar]) {
+            if (VMVariable::TYPE_STRING !== $keyVar->type) {
+                continue;
+            }
+            $serverKey = $keyVar->toString();
+            $headerName = Superglobals::serverKeyToHeaderName($serverKey);
+            if (null === $headerName) {
+                continue;
+            }
+            $resolved = $valueVar->resolveIndirect();
+            if (VMVariable::TYPE_STRING !== $resolved->type) {
+                continue;
+            }
+
+            $serverKeyStr = $context->builder->load(
+                $context->constantStringFromString($serverKey)
+            );
+            $headerKeyStr = $context->builder->load(
+                $context->constantStringFromString($headerName)
+            );
+            $valueBox = $context->builder->call(
+                $context->lookupFunction('__hashtable__readStringKeyValue'),
+                $serverPtr,
+                $serverKeyStr
+            );
+            $valueStr = $context->builder->call(
+                $context->lookupFunction('__value__readString'),
+                $valueBox
+            );
+            $context->builder->call(
+                $context->lookupFunction('__hashtable__setStringKeyString'),
+                $result,
+                $headerKeyStr,
+                $valueStr
+            );
+        }
+
+        return $result;
+    }
+}
diff --git a/ext/standard/getallheaders_.php b/ext/standard/getallheaders_.php
index b0d9a9dd..fd7b6c3d 100644
--- a/ext/standard/getallheaders_.php
+++ b/ext/standard/getallheaders_.php
@@ -14,7 +14,7 @@
 use PHPLLVM\Value;
 
 /**
- * getallheaders() — request headers from $_SERVER HTTP_* entries (VM only; issue #307).
+ * getallheaders() — request headers from $_SERVER HTTP_* entries (issue #307).
  */
 final class getallheaders_ extends Internal
 {
@@ -40,6 +40,10 @@ public function execute(Frame $frame): void
 
     public function call(Context $context, JITVariable ...$args): Value
     {
-        throw new \LogicException('getallheaders() is not implemented for JIT in this compiler build');
+        if (\count($args) > 0) {
+            throw new \LogicException('getallheaders() takes no arguments');
+        }
+
+        return JitGetallheaders::invoke($context);
     }
 }
diff --git a/lib/JIT.php b/lib/JIT.php
index 27f524e6..ce3fcbf3 100644
--- a/lib/JIT.php
+++ b/lib/JIT.php
@@ -755,6 +755,14 @@ private function assignOperand(Operand $result, Variable $value): void {
                         $owned
                     );
 
+                    return;
+                case Variable::TYPE_HASHTABLE:
+                    $this->context->builder->call(
+                        $this->context->lookupFunction('__value__writeHashtable'),
+                        $valueRef,
+                        $this->context->helper->loadValue($value)
+                    );
+
                     return;
                 case Variable::TYPE_VALUE:
                     $loaded = $this->context->builder->load($this->context->helper->loadValue($value));
diff --git a/test/compliance/cases/stdlib/getallheaders_jit.phpt b/test/compliance/cases/stdlib/getallheaders_jit.phpt
new file mode 100644
index 00000000..a6667c00
--- /dev/null
+++ b/test/compliance/cases/stdlib/getallheaders_jit.phpt
@@ -0,0 +1,14 @@
+--TEST--
+stdlib getallheaders() JIT from CGI HTTP_* environment (issue #307)
+--ENV--
+REQUEST_METHOD=GET
+HTTP_X_TEST=1
+HTTP_HOST=example.test
+--FILE--
+<?php
+$headers = getallheaders();
+echo array_key_exists('X-Test', $headers) ? 'yes' : 'no', "\n";
+echo $headers['Host'], "\n";
+--EXPECT--
+yes
+example.test
diff --git a/test/fixtures/aot/cases/getallheaders.phpt b/test/fixtures/aot/cases/getallheaders.phpt
new file mode 100644
index 00000000..2102d823
--- /dev/null
+++ b/test/fixtures/aot/cases/getallheaders.phpt
@@ -0,0 +1,14 @@
+--TEST--
+AOT: getallheaders() from CGI HTTP_* environment
+--ENV--
+REQUEST_METHOD=GET
+HTTP_X_TEST=1
+HTTP_HOST=example.test
+--FILE--
+<?php
+$headers = getallheaders();
+echo array_key_exists('X-Test', $headers) ? 'yes' : 'no', "\n";
+echo $headers['Host'], "\n";
+--EXPECT--
+yes
+example.test