This study examines the relationship between ownership structure and performance of public firms in Mexico, considering debt and the structure of the board of directors as contextual and institutional factors. This research seeks to explain the mixed results about the relationship of ownership and performance presented by other relevant studies in family and non-family businesses, mainly in emerging countries. The results confirm the positive association between family ownership concentration and performance, calculated by Tobin's Q, showing how the participation of inside shareholders on the board and a low debt level contribute to higher performance. However, the association of these variables with performance shows a contrasting effect in the case of family as compared to non-family businesses. The particular corporate legal context in Mexico could be highlighted as one of the main reasons for these results.