We examined the relationship between seasonal affective disorder (SAD) and investor response to a firm's quarterly earnings announcements. Our results show that the market's cumulative abnormal returns are associated with unexpected earnings and with SAD. Investors respond more negatively when earnings are announced in the fall than in other seasons. We also found an asymmetric SAD effect that is more significant for positive earnings announcements, on average. Moreover, the SAD affect is most evident in stocks that are more salient to investors. (C) 2015 Elsevier Inc. All rights reserved.