Purpose <p>To explore the factors influencing the untimely receipt of intravitreal anti-vascular endothelial growth factor (VEGF) injections in patients with diabetic macular edema (DME), based on the capability, opportunity, and motivation-behavior (COM-B) model.</p> Design <p>An exploratory qualitative study was conducted with semi-structured interviews with DME patients who had received at least one injection of anti-VEGF therapy within one year. The COM-B model was utilized to guide both data collection and analysis.</p> Results <p>Themes and subthemes were identified. Psychological capability for timely intravitreal anti-VEGF treatment included lack of relevant knowledge and choice of more convenient treatments. Social opportunity included no mention of intravitreal anti-VEGF therapy and effective doctor-patient communication; physical opportunity included unavailability of anti-VEGF and high treatment costs. Reflective motivation included lack of confidence in the efficacy and unmet expectations; automatic motivation included fear of injections, and fear of blindness.</p> Conclusion <p>This study identified the facilitators and barriers that influenced the timely intravitreal anti-VEGF injections, which lays the foundation for the development of future interventions.</p>