This paper aims to test and validate a model of internal factors influencing the capacity expansion decisions of family businesses, thereby helping these organizations better understand their decision-making processes. The identified internal factors include socio-emotional wealth, intergenerational cooperation, and a heterogeneous top management team. The study focuses on family businesses in the Portuguese food industry and employs both qualitative and quantitative methods. A structured online questionnaire, completed by 150 respondents, was analyzed using SPSS. Additionally, in-depth interviews were conducted to confirm the quantitative findings and provide a broader conceptual perspective. The results indicate that both qualitative and quantitative analyses support the proposed model.