Abstract: Across five studies, we show that firming one's muscles can help firm willpower and that firmed willpower mediates one's ability to withstand immediate pain, overcome food temptation, consume unpleasant medicines, and attend to immediately disturbing but essential information, provided that doing so is seen as providing long-term benefits. We draw on theories of embodied cognition to explain our results, and we add to that literature by showing for the first time that one’s body can help firm willpower and facilitate the self-regulation essential for the attainment of long-term goals.