The middle years of adulthood are often accompanied by significant psychological, social, and physical transitions, making happiness and well-being a crucial area of concern. Rajyoga lifestyle, rooted in the principles of Raja Yoga meditation and holistic living, emphasizes awareness, self-discipline, moral values, and spiritual connection. Scholars have increasingly investigated its influence on subjective well-being and life satisfaction, yet a comprehensive synthesis is still limited. This review paper critically examines research published between 2015 and 2025 that explores the impact of Rajyoga lifestyle on happiness among middle-aged adults. The literature indicates that individuals practicing Rajyoga lifestyle experience greater emotional stability, social connectedness, and resilience against stress, contributing to higher levels of happiness. Furthermore, Rajyoga appears to provide protective benefits against age-related challenges such as occupational stress, relationship strains, and declining physical health. However, existing studies reveal variations in methodological rigor, sample diversity, and cross-cultural generalizability. By consolidating theoretical insights and empirical findings, this paper highlights the mechanisms through which Rajyoga lifestyle enhances happiness, identifies research gaps, and proposes directions for future inquiry. The review underscores the need for longitudinal and cross-cultural studies, particularly in the context of middle-aged adults, to establish stronger causal evidence and integrate Rajyoga practices into mainstream well-being interventions.