<p>Adverse childhood experiences (ACEs) are consistently associated with adverse health and behavioural outcomes, including sexual risk behaviours (SRBs). However, limited research has examined associations between ACEs and sexting, an increasingly prevalent form of technology-mediated sexual interaction. This study investigated relationships between cumulative ACE exposure, SRBs, and sexting behaviours among Canadian adolescents and young adults. Data were drawn from wave two of the Canadian Study of Adolescent Health Behaviors (<i>n</i> = 912). SRBs included age of first sexual intercourse, number of sexual partners, condom use, and alcohol/drug use at last intercourse. Sexting behaviours included sending, receiving (including non-consensual), and requesting sexual images or videos in the past 12 months. Adjusted analyses revealed threshold effects, with five or more ACEs significantly associated with earlier sexual debut (β = -1.14, <i>p</i> &lt; .001) and a greater number of lifetime sexual partners (β = 2.04, <i>p</i> &lt; .05). Four ACEs were also associated with higher odds of alcohol/drug use at last intercourse (AOR = 2.22, <i>p</i> &lt; .05). ACE exposure demonstrated stronger and more consistent associations with sexting behaviours – participants reporting five or more ACEs had significantly elevated odds of engaging in all sexting outcomes, especially non-consensual experiences. Findings underscore the cumulative impact of ACEs on both offline and digitally mediated sexual behaviours, highlighting the importance of social work interventions that are sensitive to early adversity, stress responses, and developmental and psychosocial contexts.</p>