Substitute addictions – addictions that replace terminated substance use disorders (sud s) – involving addictive behaviours such as a new substance, food/eating, gambling, shopping, or sex, have implications for recovery but remain poorly understood. While extant studies suggest a multifaceted aetiology, research is needed to illuminate the nature, dynamics/mechanisms, motives and risk factors of substitute addictions. This multiple-methods study (1) reviewed the available literature on substitute addiction in people with sud s using a scoping review method; (2) explored the experience of substitute addiction from a first-person perspective using a case study; (3) investigated the prevalence of substitute addiction and associated factors among service users during and after residential substance use treatment using a quantitative longitudinal cohort design (n=137, 66% follow-up rate); (4) explored recovery support group members’ (n=23) perceptions and experiences of substitute addictions using in-depth interviews; and (5) explored service providers’ (n=22) perceptions of substitute addiction through focus group discussions. Findings were integrated across datasets to offer recommendations for prevention, practice and research.