Recent work has explored the dynamics of secrecy and its outcomes, but has yet to examine the motivations people have for engaging in secrecy and how such motivations shape the experience of secrecy and its implications. We present a motivational model of secrecy, and test this model in diverse contexts: (a) politics (secret votes in the 2016 United States election), (b) common secrets people keep, and (c) romantic relationships (secrets from partners) across a large sample of participants (total N = 1,839). We explored the motivations people have for keeping a secret, and the psychological implications of having a secret for one’s self and relationships. We found that mind wandering to secrets (but not concealing secrets) was associated with feelings of inauthenticity and regret. Moreover, it was secrecy motivated by concern for one’s reputation rather than one’s relationships that predicted these harms of secrecy.