diff --git a/classes/element.registry.php b/classes/element.registry.php
index 04b8d47de..c33e56524 100644
--- a/classes/element.registry.php
+++ b/classes/element.registry.php
@@ -3,6 +3,9 @@
 declare(strict_types=1);
 
 return [
+    'urn:oasis:names:tc:SAML:2.0:protocol:ext:async-slo' => [
+        'Asynchronous' => '\SimpleSAML\SAML2\XML\aslo\Asynchronous',
+    ],
     'urn:oasis:names:tc:SAML:metadata:algsupport' => [
         'DigestMethod' => '\SimpleSAML\SAML2\XML\alg\DigestMethod',
         'SigningMethod' => '\SimpleSAML\SAML2\XML\alg\SigningMethod',
diff --git a/resources/schemas/saml-async-slo-v1.0.xsd b/resources/schemas/saml-async-slo-v1.0.xsd
new file mode 100644
index 000000000..2a64b8917
--- /dev/null
+++ b/resources/schemas/saml-async-slo-v1.0.xsd
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<schema xmlns:aslo="urn:oasis:names:tc:SAML:2.0:protocol:ext:async-slo" 
+        xmlns="http://www.w3.org/2001/XMLSchema"  
+        targetNamespace="urn:oasis:names:tc:SAML:2.0:protocol:ext:async-slo"
+        elementFormDefault="qualified">
+    
+    <element name="Asynchronous" type="aslo:AsynchronousType" />
+    <complexType name="AsynchronousType" />
+
+    <attribute name="supportsAsynchronous" type="boolean"/>
+    
+</schema>
diff --git a/src/Constants.php b/src/Constants.php
index 968fd7817..ac884ff07 100644
--- a/src/Constants.php
+++ b/src/Constants.php
@@ -226,6 +226,11 @@ class Constants extends \SimpleSAML\XMLSecurity\Constants
      */
     public const string NS_ALG = 'urn:oasis:names:tc:SAML:metadata:algsupport';
 
+    /**
+     * The namespace for the SAML 2 Asynchronous Single Logout Profile Extension
+     */
+    public const string NS_ASLO = 'urn:oasis:names:tc:SAML:2.0:protocol:ext:async-slo';
+
     /**
      * The namespace for the ECP protocol.
      */
diff --git a/src/XML/aslo/AbstractAsloElement.php b/src/XML/aslo/AbstractAsloElement.php
new file mode 100644
index 000000000..02fdd7938
--- /dev/null
+++ b/src/XML/aslo/AbstractAsloElement.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\SAML2\XML\aslo;
+
+use SimpleSAML\SAML2\Constants as C;
+use SimpleSAML\XML\AbstractElement;
+
+/**
+ * Abstract class to be implemented by all the classes in this namespace
+ *
+ * @see https://docs.oasis-open.org/security/saml/Post2.0/saml-async-slo/v1.0/saml-async-slo-v1.0.pdf
+ * @package simplesamlphp/saml2
+ */
+abstract class AbstractAsloElement extends AbstractElement
+{
+    public const string NS = C::NS_ASLO;
+
+    public const string NS_PREFIX = 'aslo';
+
+    public const string SCHEMA = 'resources/schemas/saml-async-slo-v1.0.xsd';
+}
diff --git a/src/XML/aslo/Asynchronous.php b/src/XML/aslo/Asynchronous.php
new file mode 100644
index 000000000..50ffca5ea
--- /dev/null
+++ b/src/XML/aslo/Asynchronous.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\SAML2\XML\aslo;
+
+use Dom;
+use SimpleSAML\SAML2\Assert\Assert;
+use SimpleSAML\XML\SchemaValidatableElementInterface;
+use SimpleSAML\XML\SchemaValidatableElementTrait;
+use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
+
+/**
+ * Class representing a aslo:Asynchronous element.
+ *
+ * @package simplesaml/saml2
+ */
+final class Asynchronous extends AbstractAsloElement implements SchemaValidatableElementInterface
+{
+    use SchemaValidatableElementTrait;
+
+
+    /**
+     * Convert XML into a Asynchronous
+     *
+     * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
+     *   if the qualified name of the supplied element is wrong
+     */
+    public static function fromXML(Dom\Element $xml): static
+    {
+        Assert::same($xml->localName, 'Asynchronous', InvalidDOMElementException::class);
+        Assert::same($xml->namespaceURI, Asynchronous::NS, InvalidDOMElementException::class);
+
+        return new static();
+    }
+
+
+    /**
+     * Convert this Asynchronous to XML.
+     */
+    public function toXML(?Dom\Element $parent = null): Dom\Element
+    {
+        return $this->instantiateParentElement($parent);
+    }
+}
diff --git a/src/XML/aslo/SupportsAsynchronousTrait.php b/src/XML/aslo/SupportsAsynchronousTrait.php
new file mode 100644
index 000000000..e928a97a3
--- /dev/null
+++ b/src/XML/aslo/SupportsAsynchronousTrait.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\SAML2\XML\aslo;
+
+use SimpleSAML\XMLSchema\Type\BooleanValue;
+
+/**
+ * @package simplesamlphp/saml2
+ */
+trait SupportsAsynchronousTrait
+{
+    /** @var \SimpleSAML\XMLSchema\Type\BooleanValue|null */
+    protected ?BooleanValue $supportsAsynchronous;
+
+
+    /**
+     * @return \SimpleSAML\XMLSchema\Type\BooleanValue|null
+     */
+    public function getSupportsAsynchronous(): ?BooleanValue
+    {
+        return $this->supportsAsynchronous;
+    }
+
+
+    /**
+     * @param \SimpleSAML\XMLSchema\Type\BooleanValue $supportsAsynchronous|null
+     */
+    private function setSupportsAsynchronous(?BooleanValue $supportsAsynchronous): void
+    {
+        $this->supportsAsynchronous = $supportsAsynchronous;
+    }
+}
diff --git a/src/XML/md/SingleLogoutService.php b/src/XML/md/SingleLogoutService.php
index 6cfcf1842..414a94a76 100644
--- a/src/XML/md/SingleLogoutService.php
+++ b/src/XML/md/SingleLogoutService.php
@@ -4,6 +4,13 @@
 
 namespace SimpleSAML\SAML2\XML\md;
 
+use Dom;
+use SimpleSAML\SAML2\Assert\Assert;
+use SimpleSAML\SAML2\Type\SAMLAnyURIValue;
+use SimpleSAML\SAML2\XML\aslo\SupportsAsynchronousTrait;
+use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
+use SimpleSAML\XMLSchema\Type\BooleanValue;
+
 /**
  * SingleLogoutService element of type EndpointType
  *
@@ -11,4 +18,79 @@
  */
 final class SingleLogoutService extends AbstractEndpointType
 {
+    use SupportsAsynchronousTrait;
+
+
+    /**
+     * SingleLogoutService constructor.
+     *
+     * @param \SimpleSAML\SAML2\Type\SAMLAnyURIValue $binding
+     * @param \SimpleSAML\SAML2\Type\SAMLAnyURIValue $location
+     * @param \SimpleSAML\SAML2\Type\SAMLAnyURIValue|null $responseLocation
+     * @param \SimpleSAML\XMLSchema\Type\BooleanValue $supportsAsynchronous
+     * @param \SimpleSAML\XML\ElementInterface[] $children
+     * @param array<\SimpleSAML\XML\Attribute> $attributes
+     *
+     * @throws \SimpleSAML\Assert\AssertionFailedException
+     */
+    public function __construct(
+        SAMLAnyURIValue $binding,
+        SAMLAnyURIValue $location,
+        ?SAMLAnyURIValue $responseLocation = null,
+        protected ?BooleanValue $supportsAsynchronous = null,
+        array $children = [],
+        array $attributes = [],
+    ) {
+        $this->setSupportsAsynchronous($supportsAsynchronous);
+
+        parent::__construct($binding, $location, $responseLocation, $children, $attributes);
+    }
+
+
+    /**
+     * Initialize a SingleLogoutService.
+     *
+     * @param \Dom\Element $xml The XML element we should load.
+     *
+     * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
+     *   if the qualified name of the supplied element is wrong
+     * @throws \SimpleSAML\XMLSchema\Exception\MissingAttributeException
+     *   if the supplied element is missing any of the mandatory attributes
+     */
+    public static function fromXML(Dom\Element $xml): static
+    {
+        $qualifiedName = static::getClassName(static::class);
+        Assert::eq(
+            $xml->localName,
+            $qualifiedName,
+            'Unexpected name for endpoint: ' . $xml->localName . '. Expected: ' . $qualifiedName . '.',
+            InvalidDOMElementException::class,
+        );
+
+        return new static(
+            self::getAttribute($xml, 'Binding', SAMLAnyURIValue::class),
+            self::getAttribute($xml, 'Location', SAMLAnyURIValue::class),
+            self::getOptionalAttribute($xml, 'ResponseLocation', SAMLAnyURIValue::class, null),
+            self::getOptionalAttribute($xml, 'supportsAsynchronous', BooleanValue::class, null),
+            self::getChildElementsFromXML($xml),
+            self::getAttributesNSFromXML($xml),
+        );
+    }
+
+
+    /**
+     * Add this endpoint to an XML element.
+     *
+     * @param \Dom\Element $parent The element we should append this endpoint to.
+     */
+    public function toXML(?Dom\Element $parent = null): Dom\Element
+    {
+        $e = parent::toXML($parent);
+
+        if ($this->getSupportsAsynchronous() !== null) {
+            $e->setAttribute('supportsAsynchronous', $this->getSupportsAsynchronous()->getValue());
+        }
+
+        return $e;
+    }
 }
diff --git a/tests/SAML2/XML/aslo/AsynchronousTest.php b/tests/SAML2/XML/aslo/AsynchronousTest.php
new file mode 100644
index 000000000..09e7609b8
--- /dev/null
+++ b/tests/SAML2/XML/aslo/AsynchronousTest.php
@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\SAML2\Test\SAML2\XML\aslo;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\TestCase;
+use SimpleSAML\SAML2\XML\aslo\AbstractAsloElement;
+use SimpleSAML\SAML2\XML\aslo\Asynchronous;
+use SimpleSAML\XML\DOMDocumentFactory;
+use SimpleSAML\XML\TestUtils\SchemaValidationTestTrait;
+use SimpleSAML\XML\TestUtils\SerializableElementTestTrait;
+
+use function dirname;
+use function strval;
+
+/**
+ * Class \SimpleSAML\SAML2\XML\aslo\AsynchronousTest
+ *
+ * @package simplesamlphp/saml2
+ */
+#[Group('aslo')]
+#[CoversClass(Asynchronous::class)]
+#[CoversClass(AbstractAsloElement::class)]
+final class AsynchronousTest extends TestCase
+{
+    use SchemaValidationTestTrait;
+    use SerializableElementTestTrait;
+
+
+    /**
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$testedClass = Asynchronous::class;
+
+        self::$xmlRepresentation = DOMDocumentFactory::fromFile(
+            dirname(__FILE__, 4) . '/resources/xml/aslo_Asynchronous.xml',
+        );
+    }
+
+
+    /**
+     */
+    public function testMarshalling(): void
+    {
+        $asynchronous = new Asynchronous();
+
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($asynchronous);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
+    }
+}
diff --git a/tests/resources/xml/aslo_Asynchronous.xml b/tests/resources/xml/aslo_Asynchronous.xml
new file mode 100644
index 000000000..d4dcb6243
--- /dev/null
+++ b/tests/resources/xml/aslo_Asynchronous.xml
@@ -0,0 +1 @@
+<aslo:Asynchronous xmlns:aslo="urn:oasis:names:tc:SAML:2.0:protocol:ext:async-slo" />