Cannibalism involves killing and consuming an individual of the same species. Different factors modulate cannibalism, and here we explored whether the diet diversity would mediate the cannibalism propensity in Microlophus lizards. We compiled the available information on diet and cannibalism of the 22 Microlophus species. We found that there is a relatively high incidence of cannibalism within Microlophus, as 41% of the species exhibited this behavior. There are, however, few reports of cannibalism by each species. Cannibalism propensity showed a positive association with diet diversity, which suggests that a generalist diet might provide room for cannibalism in Microlophus lizards. We also found that only adults, mostly males, consume juveniles. Conspecific predation pressure may explain the habitat segregation among age dasses reported in some Microlophus species that exhibit cannibalism. Finally, cannibalism appears to be an ancestral condition in Microlophus, as it occurs in the two main clades of this genus. Moreover, Tropidurus, the sister taxon of Microlophus, also includes species that exhibit cannibalism, and the ancestor of these genera may have exhibited cannibalism.