diff --git a/functionMap.php b/functionMap.php
index 3c5063a..17f0291 100644
--- a/functionMap.php
+++ b/functionMap.php
@@ -32,6 +32,7 @@
  * @link https://github.com/phpstan/phpstan-src/blob/1.10.x/resources/functionMap.php
  */
 return [
+    '_wp_json_sanity_check' => ['T', '@phpstan-template' => 'T', 'value' => 'T', 'depth' => 'positive-int'],
     '_get_list_table' => ["(\$class_name is 'WP_Posts_List_Table'|'WP_Media_List_Table'|'WP_Terms_List_Table'|'WP_Users_List_Table'|'WP_Comments_List_Table'|'WP_Post_Comments_List_Table'|'WP_Links_List_Table'|'WP_Plugin_Install_List_Table'|'WP_Themes_List_Table'|'WP_Theme_Install_List_Table'|'WP_Plugins_List_Table'|'WP_Application_Passwords_List_Table'|'WP_MS_Sites_List_Table'|'WP_MS_Users_List_Table'|'WP_MS_Themes_List_Table'|'WP_Privacy_Data_Export_Requests_List_Table'|'WP_Privacy_Data_Removal_Requests_List_Table' ? T : false)", '@phpstan-template' => 'T', 'class_name' => 'class-string<T>', 'args' => 'array{screen?: string}'],
     'addslashes_gpc' => ['T', '@phpstan-template' => 'T', 'gpc' => 'T'],
     'add_submenu_page' => [null, 'callback' => "''|callable"],
diff --git a/tests/TypeInferenceTest.php b/tests/TypeInferenceTest.php
index bdf00c8..b2edf2f 100644
--- a/tests/TypeInferenceTest.php
+++ b/tests/TypeInferenceTest.php
@@ -10,6 +10,7 @@ class TypeInferenceTest extends \PHPStan\Testing\TypeInferenceTestCase
     public function dataFileAsserts(): iterable
     {
         yield from $this->gatherAssertTypes(__DIR__ . '/data/_get_list_table.php');
+        yield from $this->gatherAssertTypes(__DIR__ . '/data/_wp_json_sanity_check.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/current_time.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/echo_parameter.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/get_approved_comments.php');
diff --git a/tests/data/_wp_json_sanity_check.php b/tests/data/_wp_json_sanity_check.php
new file mode 100644
index 0000000..ec06d94
--- /dev/null
+++ b/tests/data/_wp_json_sanity_check.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpStubs\WordPress\Core\Tests;
+
+use stdClass;
+
+use function PHPStan\Testing\assertType;
+use function _wp_json_sanity_check;
+
+assertType('null', _wp_json_sanity_check(null, 1));
+assertType('bool', _wp_json_sanity_check((bool)$_GET['value'], 1));
+assertType('int', _wp_json_sanity_check((int)$_GET['value'], 1));
+assertType('string', _wp_json_sanity_check((string)$_GET['value'], 1));
+assertType('array', _wp_json_sanity_check((array)$_GET['value'], 1));
+assertType('stdClass', _wp_json_sanity_check(new stdClass(), 1));
+assertType('mixed', _wp_json_sanity_check($_GET['value'], 1));
diff --git a/wordpress-stubs.php b/wordpress-stubs.php
index 6843940..ef7e231 100644
--- a/wordpress-stubs.php
+++ b/wordpress-stubs.php
@@ -114096,6 +114096,10 @@ function wp_json_encode($value, $flags = 0, $depth = 512)
      * @param mixed $value Variable (usually an array or object) to encode as JSON.
      * @param int   $depth Maximum depth to walk through $value. Must be greater than 0.
      * @return mixed The sanitized data that shall be encoded to JSON.
+     * @phpstan-template T
+     * @phpstan-param T $value
+     * @phpstan-param positive-int $depth
+     * @phpstan-return T
      */
     function _wp_json_sanity_check($value, $depth)
     {