Diet and sex are important determinants of lifespan. In humans, high sugar diets, obesity, and type 2 diabetes correlate with decreased lifespan, and females generally live longer than males. The nematode Caenorhabditis elegans is a classical model for aging studies, and has also proven useful for characterizing the response to high‐glucose diets. However, studies on male animals are lacking. We found a surprising dichotomy: glucose regulates lifespan and aging in a sex‐specific manner, with beneficial effects on males compared to toxic effects on hermaphrodites. High‐glucose diet resulted in greater mobility with age for males, along with a modest increase in median lifespan. In contrast, high‐glucose diets decrease both lifespan and mobility for hermaphrodites. Understanding sex‐specific responses to high‐glucose diets will be important for determining which evolutionarily conserved glucose‐responsive pathways that regulate aging are “universal” and which are likely to be cell‐type or sex‐specific.