We have asked how sensory adaptation is represented the response of a population of visual motion neurons, and whether the neural adaptation could drive behavioral adaptation. Our approach was to evaluate the effects of ~10 seconds of motion adaptation on both smooth pursuit eye movements and the responses of neuron populations in extrastriate area MT in awake monkeys. Stimuli for neural recordings consisted of patches of 100% correlated dot textures. There was a wide range of effects across neurons, but on average adaptation reduced the amplitude and width of the direction tuning curves of MT neurons, without large changes in preferred direction. The effects were largest when the direction of the adapting stimulus corresponded to the preferred direction of the MT neuron under study. Adaptation also reduced the amplitude of speed tuning curves, again with the largest effect when adapting speed was equal to preferred speed. The adapted tuning curves were shifted toward lower preferred speeds as adapting speed increased. We constructed populations of model MT neurons based on our experimental sample, and showed that the effects of adaptation on the direction and speed of pursuit eye movements were predicted when a variant of vector averaging decoded the responses of a subset of the neural population. We conclude that the effects of motion adaptation on the responses of MT neurons can support behavioral adaptation in pursuit eye movements.