Family businesses play a significant role in the economies of countries worldwide. These businesses employ about half of the world’s workforce and produce over half of the world’s Gross Domestic Product (GDP). In the European Union and the United States, family business ranges from one-third to 70% of all business enterprises and produce about 20% to 70% of the GDP, employing 27% to 70% of all employees. Despite the contributions to the economy, little is known about the effect of gender on the growth and sustainability of family businesses in Tanzania. This study aimed at exploring how gender relationships affect family business growth. Specifically, the study examined the positive and negative impacts on family business. Data were collected qualitatively through in-depth interviews from 12 interviewees with family businesses in Dar-Es-Salaam. The interviewees were obtained through purposive and snowball sampling techniques. Data were analysed qualitatively based on emerging themes in such a way that the data were transcribed, coded, narrated and finally interpreted, which is a content analysis method. The study revealed that communication and transparency, trust, love and commitment, faithfulness, shared values, family unity and support affect positively the family business, whereas jealousy, family conflicts, extended family, lack of cooperation and failure to respect spousal suggestion, failure to balance between the family and business roles affect the family business negatively. Separating roles between the business and family, formalization of the business, developing job descriptions, using family protocol manual for decision making and conflict resolution, establishing an equitable reward system and providing education to the youth were recommended for the betterment of family businesses