Colour pattern are widespread in the animal kingdom and have various functions that play key roles in many ecological interactions. We present a novel function for the evolution of banded stripes in preventing cannibalism in snakes that feed on other snakes—ophiophagy. We first examined the phylogenetic relationship between ophiophagy and banded stripes by categorising pattern types and known diet of 3,568 snake species. We then conducted a series of behavioural predation experiments with California kingsnake (Lampropeltis californiae) morphs, with and without band stripes, and a non- ophiophagous prey species, the corn snake (Elaphe guttata). We found 75% of ophiophagous snakes had banded stripe patterns. Body pattern type and ophiophagy was highly conserved across snake phylogeny, and the evolution of ophiophagy was co-dependent with banded stripe patterns. Our behavioural experiments revealed banded stripes on both inter- and intraspecific prey subjects reduced the probability of predation attempts, and that kingsnakes took longer to strike prey with banded stripes. Overall, the evolution of ophiophagy in snakes appears to be facilitated by the evolution of banded stripe patterns and may help reduce cannibalism in ophiophagous species.