ABSTRACTThis paper adds to prior literature by examining whether requiring the assurance of non‐financial information increases audit fees. Specifically, we use a sample of New Zealand not‐for‐profits (charities) newly required to prepare statements of service performance (SSP), following accounting standards and assured per auditing standards. We find evidence of a significant increase in audit fees, although there is no change in audit or filing lag. There is some evidence that adopting the New Zealand‐specific auditing standard for SSPs can reduce the increase in audit fees for smaller not‐for‐profits. Overall, our results suggest mandating non‐financial information should be viewed as having increased costs. These results are particularly salient considering the ever‐increasing push for non‐financial and sustainability information throughout the world.