This paper analyses the impact of climate variability on cereal, root, and tuber crops diversification for selected West Africa countries during the period 1965- 2014. Crop diversification index, lumping together cereal, root and tuber crops, was calculated through the Composite Entropy Index. Climate variability is measured by the coefficient of variation of temperature and precipitation. A Seemingly Unrelated Regression was used to estimate the relationship between climate variability and crop diversification by controlling for supply and demand side factors of crop diversification. Overall, the results reveal that variability in temperature and precipitation over decades did not have an adverse effect on cereal root and tuber crops diversification. A detail analysis showed that Niger and Togo have been the most adapted to climate variability while Ghana was the most affected, mainly by precipitation variability. The results also indicated that, on the supply side, the availability of agricultural land contributed to crop diversification. Productivity, which is expected to increase crop diversification, was positive and significant in very few countries. In the others, it was not enough to improve crop diversification. On the demand side, population growth and consumption led to crop diversification, particularly in consumption of roots and tuber crops. This study suggests that greater diversification would mitigate the negative impact of climate variability. Therefore, regional, and national agricultural policies aimed at increasing productivity are necessary to encourage farmers to diversify food crops under climate variability.