Objective: Around 40% of US university students use cannabis, 25% of whom present with cannabis use disorder, which endangers health. We investigated the concurrent contribution of reflective processes, which generate action via conscious deliberation, and non-reflective processes, which prompt behavior automatically, to undergraduates' cannabis consumption. Participants: Eighteen UK undergraduates who regularly consume cannabis (11 female, 7 male; mean age 20 y). Methods: Semi-structured interviews explored cannabis motives, routines, cues, and decision points. Thematic analysis identified themes, in each of which reflective and non-reflective dimensions were coded. Results: Four themes were identified: cannabis use for relaxation, social bonding, and symbolic-affective significance, and contexts and triggers. Some influences guided cannabis use reflectively in some settings, and non-reflectively in others. Even when cannabis use was consciously driven, non-reflective processes were deployed to execute subservient acts, such as rolling joints. Conclusions: Findings highlight specific processes and pathways that might be targeted to reduce cannabis-related harm.