question: PurposeThe purpose of this study is to identify patient experience unique to online pharmacy services (OPS) based on the characteristics of OPS (i.e. interactivity and virtuality) and to reveal how patient experience is derived from OPS and thereby enhances patient adherence from both online social support and patient experience perspectives.Design/methodology/approachThe Stimulus-Organism-Response framework was used to conceptualize this study;both primary and secondary data for 296 validated participants were collected on a real OPS platform. A structural equation modeling approach combined with partial least squares was employed for the quantitative analysis.FindingsSocial presence and user engagement can be identified as patient experience in the OPS context;online emotional support has a stronger association with patients' social presence than it does with patients' user engagement;patients' social presence has a stronger association with their medication adherence than it does with diet adherence, while patients' user engagement has a stronger association with their diet adherence than it does with medication adherence;patients' medication knowledge negatively moderates the relationship between user engagement and diet adherence.Originality/valueThis study identifies patient experience in accordance with unique characteristics of OPS, and it reveals the nuanced underlying mechanisms by which online social support is associated with patient experience and by which patients' experience is associated with their adherence. This study enriches the literature on patient adherence, patient experience and OPS, providing insights for healthcare providers, OPS designers and policymakers.