diff --git a/doc/repo/custom_properties.md b/doc/repo/custom_properties.md
new file mode 100644
index 00000000000..bc987c4da20
--- /dev/null
+++ b/doc/repo/custom_properties.md
@@ -0,0 +1,28 @@
+## Repo / Custom Properties API
+[Back to the "Repos API"](../repos.md) | [Back to the navigation](../README.md)
+
+For extended info see the [GitHub documentation](https://docs.github.com/en/rest/reference/repos#custom-properties-for-a-repository)
+
+### List custom properties for a repository
+
+```php
+$properties = $client->api('repo')->properties()->all('twbs', 'bootstrap');
+```
+
+### Get a custom property for a repository
+
+```php
+$property = $client->api('repo')->properties()->show('twbs', 'bootstrap', $propertyName);
+```
+
+
+### Update a custom property for a repository
+
+```php
+$parameters = [
+    'property_name' => 'foo',
+    'value' => 'bar'
+]
+
+$property = $client->api('repo')->properties()->update('twbs', 'bootstrap', $params);
+```
diff --git a/lib/Github/Api/Repo.php b/lib/Github/Api/Repo.php
index 5653ae4c152..6c65514e3a4 100644
--- a/lib/Github/Api/Repo.php
+++ b/lib/Github/Api/Repo.php
@@ -15,6 +15,7 @@
 use Github\Api\Repository\Comments;
 use Github\Api\Repository\Commits;
 use Github\Api\Repository\Contents;
+use Github\Api\Repository\CustomProperties;
 use Github\Api\Repository\DeployKeys;
 use Github\Api\Repository\Downloads;
 use Github\Api\Repository\Forks;
@@ -523,6 +524,18 @@ public function statuses()
         return new Statuses($this->getClient());
     }
 
+    /**
+     * Manage the custom properties of a repository.
+     *
+     * @link https://docs.github.com/en/rest/repos/custom-properties
+     *
+     * @return CustomProperties
+     */
+    public function customProperties()
+    {
+        return new CustomProperties($this->getClient());
+    }
+
     /**
      * Get the branch(es) of a repository.
      *
diff --git a/lib/Github/Api/Repository/CustomProperties.php b/lib/Github/Api/Repository/CustomProperties.php
new file mode 100644
index 00000000000..62a6bdc9a5d
--- /dev/null
+++ b/lib/Github/Api/Repository/CustomProperties.php
@@ -0,0 +1,63 @@
+<?php
+
+namespace Github\Api\Repository;
+
+use Github\Api\AbstractApi;
+use Github\Exception\RuntimeException;
+
+/**
+ * @link   https://docs.github.com/en/rest/repos/custom-properties
+ *
+ * @author Ondřej Nyklíček <ondrej@nyoncode.cz>
+ */
+class CustomProperties extends AbstractApi
+{
+    /**
+     * @param string $owner      The account owner of the repository.
+     * @param string $repository The name of the repository.
+     *
+     * @return array|string
+     */
+    public function all(string $owner, string $repository)
+    {
+        return $this->get('/repos/'.rawurlencode($owner).'/'.rawurlencode($repository).'/properties/values');
+    }
+
+    /**
+     * @param string $owner        The account owner of the repository.
+     * @param string $repository   The name of the repository.
+     * @param string $propertyName The name of the property to retrieve.
+     *
+     * @throws RuntimeException if the property is not found.
+     *
+     * @return array
+     */
+    public function show(string $owner, string $repository, string $propertyName): array
+    {
+        $allProperties = $this->all($owner, $repository);
+
+        if (!is_array($allProperties)) {
+            throw new RuntimeException('Unexpected response from GitHub API.');
+        }
+
+        foreach ($allProperties as $property => $value) {
+            if ($property === $propertyName) {
+                return ['property_name' => $property, 'value' => $value];
+            }
+        }
+
+        throw new RuntimeException("Property [$propertyName] not found.");
+    }
+
+    /**
+     * @param string               $owner      The account owner of the repository.
+     * @param string               $repository The name of the repository.
+     * @param array<string, mixed> $params
+     *
+     * @return array|string
+     */
+    public function update(string $owner, string $repository, array $params)
+    {
+        return $this->patch('/repos/'.rawurlencode($owner).'/'.rawurlencode($repository).'/properties/values', $params);
+    }
+}
diff --git a/test/Github/Tests/Api/Repository/CustomPropertiesTest.php b/test/Github/Tests/Api/Repository/CustomPropertiesTest.php
new file mode 100644
index 00000000000..18b31f0f45e
--- /dev/null
+++ b/test/Github/Tests/Api/Repository/CustomPropertiesTest.php
@@ -0,0 +1,88 @@
+<?php
+
+namespace Github\Tests\Api\Repository;
+
+use Github\Api\Repository\CustomProperties;
+use Github\Tests\Api\TestCase;
+
+class CustomPropertiesTest extends TestCase
+{
+    public function testAll()
+    {
+        $expectedArray = ['property1' => 'value1', 'property2' => 'value2'];
+
+        $api = $this->getApiMock();
+        $api->expects($this->once())
+            ->method('get')
+            ->with('/repos/owner/repo/properties/values')
+            ->willReturn($expectedArray);
+
+        $this->assertEquals($expectedArray, $api->all('owner', 'repo'));
+    }
+
+    public function testShowPropertyExists()
+    {
+        $allProperties = [
+            'property1' => 'value1',
+            'property2' => 'value2',
+        ];
+
+        $api = $this->getApiMock();
+        $api->expects($this->once())
+            ->method('get')
+            ->with('/repos/owner/repo/properties/values')
+            ->willReturn($allProperties);
+
+        $expectedResult = [
+            'property_name' => 'property2',
+            'value' => 'value2',
+        ];
+
+        $this->assertEquals($expectedResult, $api->show('owner', 'repo', 'property2'));
+    }
+
+    public function testShowPropertyDoesNotExist()
+    {
+        $allProperties = [
+            'property1' => 'value1',
+            'property2' => 'value2',
+        ];
+
+        $api = $this->getApiMock();
+        $api->expects($this->once())
+            ->method('get')
+            ->with('/repos/owner/repo/properties/values')
+            ->willReturn($allProperties);
+
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('Property [property3] not found.');
+
+        $api->show('owner', 'repo', 'property3');
+    }
+
+    public function testUpdate()
+    {
+        $params = [
+            'property1' => 'newValue1',
+            'property2' => 42,
+        ];
+
+        $expectedResponse = [
+            'property1' => 'newValue1',
+            'property2' => 42,
+        ];
+
+        $api = $this->getApiMock();
+        $api->expects($this->once())
+            ->method('patch')
+            ->with('/repos/owner/repo/properties/values', $params)
+            ->willReturn($expectedResponse);
+
+        $this->assertEquals($expectedResponse, $api->update('owner', 'repo', $params));
+    }
+
+    protected function getApiClass()
+    {
+        return CustomProperties::class;
+    }
+}