Beat gestures—spontaneously produced biphasic movements of the hand are among the most frequently encountered co-speech gestures in human communication. They are closely temporally aligned to the prosodic characteristics of the speech signal, typically occurring on lexically stressed syllables. Despite their prevalence across speakers of the world’s languages, how beat gestures impact spoken word recognition is unclear. Can these simple ‘flicks of the hand’ influence speech perception? Across a range of experiments, we demonstrate that beat gestures influence the explicit and implicit perception of lexical stress (e.g. distinguishing ‘OBject’ from ‘obJECT’), and in turn can influence what vowels listeners hear. Thus, we provide converging evidence for a manual McGurk effect-relatively simple and widely occurring hand movements influence which speech sounds we hear.