Purpose: The purpose of this study was to analyze and clarify the concept of happiness. Methods: A review of the literature was conducted using several databases. The databases were searched using the following key words: happiness, subjective well-being, and concept analysis. Literatures related to happiness were reviewed using the framework ofWalker and Avant's conceptual analysis process. Results: Happiness can be defined by the following attributes: 1) physical comfort, 2) socio-economic stability 3) comparative advantage 4) positive emotion from satisfying one's desire, 5) taking a positive view of reality, 6) satisfaction from interacting with others, 7) attainment of life goal through immersion. The antecedents of happiness are as follows: 1) characteristics, 2) basic needs, 3) cognitive system, 4) goal of life, 5) human relationship, 6) socio-economic status. The consequences of happiness are as follows: 1) positive coping mechanism of stress 2) mental health promotion. Conclusion: The theoretical definition for happiness is physical comfort and emotional pleasure related to satisfaction of personal needs in their social and cultural environment. It is satisfaction or adaptation according to personal characteristics and cognitive evaluation over the external situation. Furthermore achievement of life goal means the ultimate self-realization that brings meaningful outcome in human relationship.