diff --git a/src/Type/Php/ArrayKeyExistsFunctionTypeSpecifyingExtension.php b/src/Type/Php/ArrayKeyExistsFunctionTypeSpecifyingExtension.php
index 8ba537930d..d504a260de 100644
--- a/src/Type/Php/ArrayKeyExistsFunctionTypeSpecifyingExtension.php
+++ b/src/Type/Php/ArrayKeyExistsFunctionTypeSpecifyingExtension.php
@@ -21,6 +21,7 @@
 use PHPStan\Type\MixedType;
 use PHPStan\Type\TypeCombinator;
 use function count;
+use function in_array;
 
 class ArrayKeyExistsFunctionTypeSpecifyingExtension implements FunctionTypeSpecifyingExtension, TypeSpecifierAwareExtension
 {
@@ -38,7 +39,7 @@ public function isFunctionSupported(
 		TypeSpecifierContext $context,
 	): bool
 	{
-		return $functionReflection->getName() === 'array_key_exists'
+		return in_array($functionReflection->getName(), ['array_key_exists', 'key_exists'], true)
 			&& !$context->null();
 	}
 
diff --git a/src/Type/Php/TypeSpecifyingFunctionsDynamicReturnTypeExtension.php b/src/Type/Php/TypeSpecifyingFunctionsDynamicReturnTypeExtension.php
index 628dfa7be6..d28f3c5075 100644
--- a/src/Type/Php/TypeSpecifyingFunctionsDynamicReturnTypeExtension.php
+++ b/src/Type/Php/TypeSpecifyingFunctionsDynamicReturnTypeExtension.php
@@ -39,6 +39,7 @@ public function isFunctionSupported(FunctionReflection $functionReflection): boo
 	{
 		return in_array($functionReflection->getName(), [
 			'array_key_exists',
+			'key_exists',
 			'in_array',
 			'is_numeric',
 			'is_int',
diff --git a/tests/PHPStan/Analyser/NodeScopeResolverTest.php b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
index 1c2b7a69c6..b4ebdfdf5a 100644
--- a/tests/PHPStan/Analyser/NodeScopeResolverTest.php
+++ b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
@@ -1011,6 +1011,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-6170.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/../Rules/Arrays/data/slevomat-foreach-array-key-exists-bug.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/array-key-exists.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/key-exists.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-7909.php');
 
 		if (PHP_VERSION_ID >= 80000) {
diff --git a/tests/PHPStan/Analyser/TypeSpecifierTest.php b/tests/PHPStan/Analyser/TypeSpecifierTest.php
index f1791cb923..052906f97f 100644
--- a/tests/PHPStan/Analyser/TypeSpecifierTest.php
+++ b/tests/PHPStan/Analyser/TypeSpecifierTest.php
@@ -954,6 +954,54 @@ public function dataCondition(): array
 					'$array' => '~hasOffset(\'foo\')',
 				],
 			],
+			[
+				new Expr\BinaryOp\BooleanOr(
+					new FuncCall(new Name('key_exists'), [
+						new Arg(new String_('foo')),
+						new Arg(new Variable('array')),
+					]),
+					new FuncCall(new Name('key_exists'), [
+						new Arg(new String_('bar')),
+						new Arg(new Variable('array')),
+					]),
+				),
+				[
+					'$array' => 'array',
+				],
+				[
+					'$array' => '~hasOffset(\'bar\')|hasOffset(\'foo\')',
+				],
+			],
+			[
+				new BooleanNot(new Expr\BinaryOp\BooleanOr(
+					new FuncCall(new Name('key_exists'), [
+						new Arg(new String_('foo')),
+						new Arg(new Variable('array')),
+					]),
+					new FuncCall(new Name('key_exists'), [
+						new Arg(new String_('bar')),
+						new Arg(new Variable('array')),
+					]),
+				)),
+				[
+					'$array' => '~hasOffset(\'bar\')|hasOffset(\'foo\')',
+				],
+				[
+					'$array' => 'array',
+				],
+			],
+			[
+				new FuncCall(new Name('key_exists'), [
+					new Arg(new String_('foo')),
+					new Arg(new Variable('array')),
+				]),
+				[
+					'$array' => 'array&hasOffset(\'foo\')',
+				],
+				[
+					'$array' => '~hasOffset(\'foo\')',
+				],
+			],
 			[
 				new FuncCall(new Name('is_subclass_of'), [
 					new Arg(new Variable('string')),
diff --git a/tests/PHPStan/Analyser/data/key-exists.php b/tests/PHPStan/Analyser/data/key-exists.php
new file mode 100644
index 0000000000..678bc368a9
--- /dev/null
+++ b/tests/PHPStan/Analyser/data/key-exists.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace KeyExists;
+
+use function key_exists;
+use function PHPStan\Testing\assertType;
+
+class KeyExists
+{
+	/**
+	 * @param array<string, string> $a
+	 * @return void
+	 */
+	public function doFoo(array $a, string $key): void
+	{
+		assertType('false', key_exists(2, $a));
+		assertType('bool', key_exists('foo', $a));
+		assertType('false', key_exists('2', $a));
+
+		$a = ['foo' => 2, 3 => 'bar'];
+		assertType('true', key_exists('foo', $a));
+		assertType('true', key_exists('3', $a));
+		assertType('false', key_exists(4, $a));
+
+		$empty = [];
+		assertType('false', key_exists('foo', $empty));
+		assertType('false', key_exists($key, $empty));
+	}
+}