Background: Health promotion psychology is increasingly central to public health because it addresses behavioral determinants of health, chronic disease burden, and mental health inequalities. In Greece, prolonged socioeconomic pressures, ongoing health-system reforms, and persistent mental health challenges create a distinctive context for the development and implementation of psychologically informed health promotion strategies. Aim: To map the evidence base on health promotion psychology in Greece, identifying thematic foci, methodological patterns, and implementation barriers. Methods: A mapping review of peer-reviewed publications and selected institutional sources (2000–2025) was conducted across international and Greek databases (e.g., PubMed, Scopus, PsycINFO, and national repositories). Eligible sources addressed prevention, behavior change, mental health promotion, biopsychosocial integration, or digital health applications in Greek populations or settings. Evidence was charted and synthesized descriptively by domain, target population, setting, study design, and evaluation characteristics. Results: The mapped evidence (n = 58 studies) indicates growing engagement with biopsychosocial and preventive frameworks, expansion of mental health promotion initiatives (particularly youth- and school-based programs), and emerging interest in digital and gamified interventions. Translation remains constrained by biomedical dominance, fragmented service delivery, limited integration of psychological expertise into policy, scarce long-term and implementation-focused evaluations, and limited training pathways in health promotion psychology. Conclusions: Health promotion psychology in Greece is developing but remains unevenly embedded within health systems and policy. Priorities include strengthening interdisciplinary implementation structures, culturally responsive and equity-oriented design, workforce development, and systematic evaluation to support scalable and sustainable public health impact.