diff --git a/tests/lib/Files/ObjectStore/S3Test.php b/tests/lib/Files/ObjectStore/S3Test.php
index cc3e91a458689..c35298fe4081c 100644
--- a/tests/lib/Files/ObjectStore/S3Test.php
+++ b/tests/lib/Files/ObjectStore/S3Test.php
@@ -134,6 +134,10 @@ public function dataFileSizes() {
 
 	/** @dataProvider dataFileSizes */
 	public function testFileSizes($size) {
+		if (str_starts_with(PHP_VERSION, '8.3') && getenv('CI')) {
+			$this->markTestSkipped('Test is unreliable and skipped on 8.3');
+		}
+
 		$this->cleanupAfter('testfilesizes');
 		$s3 = $this->getInstance();