Butterflies display incredible ecological and behavioural diversity. As such, they have been subject to intense study since the birth of evolutionary biology. However, with some possible exceptions, they are underused models in comparative and functional neurobiology. We highlight a series of areas, spanning sensory ecology to cognition, in which butterflies are particularly promising systems for investigating the neurobiological basis for behavioural or ecological variation. These fields benefit from a history of molecular and quantitative genetics, and basic comparative neuroanatomy, but these strands of research are yet to be widely integrated. We discuss areas for potential growth and argue that new experimental techniques, growing genomic resources, and tools for functional genetics will accelerate the use of butterflies in neurobiology.