Although the field of family businesses has been regarded as a separate academic discipline since the 1990s in the world, in Iran no particular study has been done in this field. Furthermore, growth of firms is very important in the firm's survival. We investigated and explained the factors affecting growth and development of family businesses in Tehran.Almost 78 family businesses in textile industry and 80 family businesses in oil industry were identified. A sample of 88 firms from two industries was examined in our study. Findings show that there are correlations between growth and independent factors such as risk taking of owner managers, orientation to innovation, skills related to management, people interest to participate in their family business, strategic insight of family members, political environment, cultural environment and economical environment, and there is no correlation between growth and the governance of family on their business.