This paper analyses tax aggressiveness in family firm generations. Moreover, taking into account the heterogeneity in family firms, we check whether the successive generations in control show different tax avoidance behaviour. The empirical evidence, based on the qua-si-experiment of the 2012 Spanish thin capitalization rule, reveals that there is a positive relationship between tax aggressiveness and successive generations. Moreover, the founder and second generations follow a similar conservative tax avoidance approach, whereas the third and fourth generations are found to be more tax aggressive.