This study investigates the determinants of firms’ decision to impair goodwill under IFRS. Our empirical analysis is based on data for the years 2005 to 2011 for 8,110 non-financial firm-years and 1,358 financial firm-years from 21 countries where firms apply IFRS. We specifically investigate which role national enforcement systems play for firms’ decisions whether or not to impair goodwill. We find that firms’ decisions are related to measures of performance, but also to proxies for managerial and firm-level incentives. We also find that goodwill impairment is associated with lagged stock-market return, suggesting that firms tend to delay necessary impairment. Further investigations reveal that the timeliness of goodwill impairment depends on the strength of national accounting and auditing enforcement systems: in countries with weak enforcement systems firms tend to delay necessary goodwill impairments, while firms in countries with strong enforcement systems tend to write off goodwill in a timely fashion, both before and after the Financial Crisis. However, even in countries with strict enforcement impairment decisions appear to be influenced by managerial and firm-level incentives, such as CEO reputation concerns and by management’s preferences for smooth earnings.