Open innovation has emerged as a topic of great importance due to the recognized benefits that it brings to the company's business performance; however, it has been sparsely addressed in SMEs from developing countries. Therefore, this study aims to analyze and discuss the relationship between open innovation and business performance in family and non-family SMEs in Mexico. A survey-based study was carried out on a sample of 308 firms. Following this, the data was analyzed through a structural equation model. The results show that for these companies, the outflow and especially the inflow of external knowledge exert a positive influence on business performance.