diff --git a/functionMap.php b/functionMap.php
index 09beaec..e8b0277 100644
--- a/functionMap.php
+++ b/functionMap.php
@@ -281,6 +281,7 @@
     'wp_internal_hosts' => ['array<lowercase-string>'],
     'wp_is_numeric_array' => ['($data is array<int, mixed> ? true : false)', '@phpstan-pure' => ''],
     'wp_is_post_revision' => ['($post is \WP_Post ? false|int<0, max> : ($post is int<min, 0> ? false : false|int<0, max>))'],
+    'wp_is_stream' => [null, '@phpstan-assert-if-true' => '=non-falsy-string $path'],
     'wp_is_uuid' => ['($version is 4|null ? bool : false)', 'uuid' => 'TUuid', 'version' => '4', '@phpstan-template TUuid' => 'of string', '@phpstan-assert-if-true' => '=TUuid&lowercase-string&non-falsy-string $uuid', '@phpstan-pure' => ''],
     'wp_json_encode' => ['non-empty-string|false', 'depth' => 'int<1, max>'],
     'wp_latest_comments_draft_or_post_title' => ['non-falsy-string'],
diff --git a/tests/data/assert/wp-is-stream.php b/tests/data/assert/wp-is-stream.php
new file mode 100644
index 0000000..9de123f
--- /dev/null
+++ b/tests/data/assert/wp-is-stream.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpStubs\WordPress\Core\Tests;
+
+use function wp_is_stream;
+use function PHPStan\Testing\assertType;
+
+// if wp_is_stream() returns true, then $path is a non-falsy string
+// with no effect on the type of $path if it returns false
+
+$path = Faker::string();
+if (wp_is_stream($path)) {
+    assertType('non-falsy-string', $path);
+}
+assertType('string', $path);
+
+$path = Faker::lowercaseString();
+if (wp_is_stream($path)) {
+    assertType('lowercase-string&non-falsy-string', $path);
+}
+assertType('lowercase-string', $path);
+
+// if wp_is_stream() returns false, $path is not narrowed
+// with no effect on the type of $path if it returns true
+
+$path = Faker::string();
+if (! wp_is_stream($path)) {
+    assertType('string', $path);
+}
+assertType('string', $path);
+
+$path = Faker::lowercaseString();
+if (! wp_is_stream($path)) {
+    assertType('lowercase-string', $path);
+}
+assertType('lowercase-string', $path);
diff --git a/wordpress-stubs.php b/wordpress-stubs.php
index a51a121..5c2a9dd 100644
--- a/wordpress-stubs.php
+++ b/wordpress-stubs.php
@@ -134583,6 +134583,7 @@ function _device_can_upload()
      *
      * @param string $path The resource path or URL.
      * @return bool True if the path is a stream URL.
+     * @phpstan-assert-if-true =non-falsy-string $path
      */
     function wp_is_stream($path)
     {