Although the visual perception of objects and motion is critical to countless animal behaviors, we are just beginning to understand the computational architecture of the neural circuits in the visual system. Fruit flies have emerged as a powerful model system for examining these circuits as a result of their rich repertoire of visually mediated behaviors, as well as the many molecular tools available for this species. We have examined the computations performed in the motion vision pathway of fruit flies using a combination of two-photon imaging, optogenetic manipulation, and behavioral experiments. This work has provided substantial insights about how motion is computed from visual stimuli, and yielded new evidence for the computational role of key neuron types.