In the last two decades, the use of oral anticancer agents (OAAs) has increased in cancer patients. Despite this, patients and their caregivers face some challenging issues (side effects, drug-to-drug interactions, etc.) related to OAA administration. The three dimensions of self-care by Riegel et al., self-care maintenance (i.e., stability of patient condition), self-care monitoring (i.e., detection of side effects), and self-care management (i.e., management of side effects), may be implemented to avoid negative outcomes. However, knowledge of self-care determinants is necessary to recognise people at risk of poor self-care behaviours. Determine which are the predictors of self-care maintenance, self-care monitoring and self-care management in patients with cancer taking OAA. A systematic review with narrative synthesis was conducted. We included studies on adult patients with cancer using any kind of oral anticancer agent and describing a predictor of self-care. The search was performed on PubMed, CINAHL/PsycINFO, and Web of Science. Of 3,061 records, 45 studies were included in this review. Forty-six predictors organised into 14 categories were identified. In general, all studies focused only on adherence, considered as a self-care maintenance component, and none of them focused on other dimensions of self-care. The predictors of OAA adherence most reported were age, side effects, and socioeconomic factors (e.g., insurance status, and annual income). This systematic review highlighted the literature gap on the analysis of determinants of self-care behaviours in patients taking OAAs. This element could be a starting point for future research that can provide elements to support the oncology nursing research agenda, aimed at recognising patients at risk of poor self-care.