The paper examines the role of non-normality risks in explaining the momentum puzzle of equity returns. It shows that momentum returns are not normally distributed. About 70 basis points of the annual momentum profits can be attributed to systematic skewness risk. This finding is pervasive across nine strategies and is reinforced when time dependencies in abnormal returns and risks are explicitly modeled. The analysis also reveals that the market and skewness risks of momentum portfolios evolve over the business cycle in a manner that is consistent with market timing and risk aversion. While the momentum puzzle still remains, these findings are in line with market efficiency.