As the life-expectancy is ever-increasing, and the proportion of the elderly population is growing steadily in every society of the world, it is ever more important to establish what factors allow certain elderly people to age successfully and remain relatively independent while others grow old less successfully and require extensive intervention. However, there is no consensus yet as to what successful aging means. Researchers have defined successful aging in a variety of ways. This study attempted to define the concept of successful aging and to clarify some dimensions of it through literature review. Previous approaches of studying successful aging and related themes were examined. Early perspectives including activity, disengagement, and continuity theories, Selective Optimization with Compensation (SOC) model by Baltes and Baltes, three different conceptions of successful aging, that is, psychological well-being, physical health, and wisdom, and MacArthur research on successful aging have been reviewed for this study. The definition derived from the review is: Keeping up continuous developmental processes to achieve wisdom or ego-integrity, without suffering any major disabilities in either physical or mental functioning, while maintaining psychological well-being and employing SOC strategies, and participating in positive relationships with significant others. The dimensions of successful aging are 1) personal resources, including physical health, cognitive competences, self esteem, and social support 2) adaptation process of SOC, and 3) psychological aspects, including psychological well-being and wisdom.