Enhancing patient-centeredness in healthcare is crucial for delivering high-quality patient care, particularly in light of concerning statistics indicating that many patients feel inadequately informed about their illnesses. Engaging patients in the development of services and systems serves as a pivotal strategy to enhance patient-centeredness. Nonetheless, existing literature lacks a comprehensive overview of patient engagement strategies, impeding stakeholders’ ability to discern co-creation opportunities. Addressing this gap, this systematic review examines patient engagement across diverse healthcare domains and methodologies. Among the 1.686 articles initially screened in PubMed, 72 met inclusion criteria and were categorized into seven distinct groups: research, clinical studies, quality management, guideline development, policy, product and innovation, and clinical organization. The findings provide a comprehensive outlook on patient engagement possibilities, underscore methodological similarities, and reveal varying levels of research and results across categories, signaling significant potential for future studies.