Whilst emphasizing adult learners' characteristics as being different from traditional students, few studies have taken into account a broad personality trait, i.e. core self-evaluation (CSE), when explaining their learning performance. Additionally, existing studies confirm the vital role of adult education in the inclusion process of citizens in our contemporary society. However, questions remain unanswered as to what specific factors of the learning environment contribute to these social outcomes, except in educational programmes explicitly directed at social inclusion. Responding to this literature gap, the present study (1) investigated the effect of CSE and online interaction quality on adults' learning performance and (2) scrutinized how online interaction quality and learning performance affect their bonding and bridging social capital. Participants (N = 140) were learners from a blended learning programme in centres for adult education in Belgium. Path analyses showed that only CSE significantly predicted adults' learning performance. Online interaction quality was found to have a significant effect on learners' bonding and bridging social capital, but not learning performance. To this end, the findings highlight the importance of dispositional factors regarding adults' achievement in a blended learning environment and the potential of such programmes to enhance their social outcomes in addition to cognitive gains.