Medication non-adherence has been recognised as one of the major problems in health care that leads to preventable costs and hospitalisations. This study aimed to assess the role of affect in medication adherence. We propose a dual-process framework of medication adherence based on the reflective–impulsive model, which includes both cognitive and affective processes. We tested this framework in a cross-sectional study (N = 525). The results supported this framework by illustrating the clear role of both cognitive and affective processes.