Social business, was first defined by Nobel Peace Prize laureate Prof. Muhammad Yunus and is described in his books. Social businesses are non-loss, non-dividend companies created to address and solve social or environmental problems. Microfinance is another form of social businesses. Like an NGO, social business has a social mission, but like a business, it generates its own revenues to cover its costs. In a social business, the investors/owners can gradually recoup the money invested, but cannot take any dividend beyond that point. The purpose of the investment is purely to achieve one or more social objectives through the operation of the company. No personal gain is desired by the investors. The company must cover all costs and be financially sustainable, while achieving the social objective in sectors such as healthcare, education, poverty, environment, housing, climate urgency etc. Legal structures available to all enterprises can be used by social businesses. These are: for-profit organizations, non-profit organizations (associations, foundations), charities, co-operatives. However, there are legal structures specifically designed of social businesses. These are: benefit corporation, flexible purpose corporation, low profit limited liability company (L3C), hybrids, community interest company (CIC).The purpose is this study is to contribute to the Turkish literature related to social businesses. In this study, definition of social business and microfinance will be given. The characteristics of social business will be indicated, social business examples will be presented and finally legal structures of social businesses will be analyzed. This study is descriptive study.