Marginalized individuals are often caught in a vicious cycle of economic or health problems, a lack of social connection and disempowerment. The present research examines interventions that provide opportunities for social inclusion to break this cycle. Specifically, in two longitudinal field studies, we examined the effect of social inclusion on self-efficacy and hope in two vulnerable groups, namely, 68 residents in a drug and alcohol rehabilitation centre (Study 1) and 48 marginalized adults taking part in activities organized by a community organization (Study 2). Although somewhat counterintuitive, we hypothesized that social inclusion would affect self-efficacy by fostering feelings of personal autonomy. The hypothesis was supported by results from both studies revealing an indirect effect from social inclusion via personal autonomy on self-efficacy and hope. The findings are discussed in relation to how group inclusion may stimulate the development of personal autonomy in disadvantaged adults, an important factor in their recovery and mental health.