The aim of this research is to test the influence of mental accounting and motivation to financial behavior and test financial self-efficacy in mediating the relationship between mental accounting and financial behavior. This research uses survey method by sending questionnaires to young entrepreneurs starting a business. The result of the research shows that mental accounting, financial self-efficacy, and motivation influence financial behavior. This research discovers that a person’s confidence in their ability in managing finance depend on mental accounting mindset. Financial self-efficacy is also an important variable for encouraging the increasing of a person’s ability in planning and managing finance.