This study investigated sext dissemination in a large convenience sample of young adults (N = 691, M age = 22.4, SD = 3.2, 53% female). Participants who disseminated sexts (17.4%) were more likely sexually active, and from a younger age, had requested sexts, received disseminated sexts, and reported higher dark triad trait levels. Images were usually received from a different gender and disseminated to the same gender. Men and women were equally likely to disseminate sexts, mainly to the same gender, whilst men tended to distribute to more individuals. Common motivations were attractiveness, humour and unimportance, with revenge uncommon. Men were more frequently motivated by attractiveness and increased social status. Four unique factors were associated with sext dissemination: having requested sexts, received disseminated sexts, had one's own sexts disseminated and elevated narcissistic traits; consistent with social exchange theory. Age, having requested sexts and having one's own images shared were associated with increased frequency of dissemination. One in ten respondents knew of their own sexts being disseminated; with men (27.9%) three times more likely than women (9.5%) to have consented to dissemination. Theoretical explanations and implications are discussed. Future interventions should focus on explicit consent and empathy, rather than punitive approaches.