Co-speech gestures in autism spectrum disorder (ASD) are poorly understood. Historically, all gestures were thought to be reduced in this social-communicative disorder; however, reduced gestures have not been consistently demonstrated in the empirical literature. Just as protodeclarative pointing is reduced in young children with ASD, while protoimperative pointing is not, the varied functions of co-speech gesture may explain these mixed findings. Verbally fluent adolescents with ASD (n = 18) and controls (n = 18) completed a narrative task and a standardized executive function task. Gestures on the narrative task, which serve a wide range of social and cognitive functions, were reduced in ASD. Gestures on the executive function task, which serve primarily cognitive functions, were increased in ASD. Gesture function may be the best predictor of the presence or absence of gesture in ASD. Despite reduced social-communicative gestures, individuals with ASD may benefit from gesture's internal, cognitive functions.