Interacting agents may anticipate their partner's upcoming response and include it in their action plan. In turn, observing an overt response can trigger agents to adapt. But although anticipation and adaptation are known to shape action control, their interplay in social interactions remains largely unexplored. In 4 experiments, we asked how both of these mechanisms could contribute to one striking phenomenon: Agents initiate actions faster when they know their partner will produce a compatible rather than an incompatible response. In Experiment 1, we manipulated the compatibility between agents' actions and partners' responses and investigated the interplay between adaptation and anticipation within the same dyadic interaction. In Experiments 2-4, we isolated the contribution of each mechanism by having agents interact with virtual partners whose responses could be experimentally controlled. We found that adaptation and anticipation exert parallel but independent effects on action execution: Participants initiated their actions more quickly when the upcoming partner response was compatible and, independently, when their partner had responded more quickly on the preceding trial. These findings elucidate models of action control in social interactions. (PsycInfo Database Record (c) 2020 APA, all rights reserved).