Summary Political knowledge is an essential determinant of citizen political participation. However, many studies have indicated that there is a gap in the political knowledge of men and women. This work aimed to extend research into the gender gap to Mexican children as a result of political socialisation (school and family) and included the consumption of social media as an interest factor. A survey (n = 1539) was carried out between April and May 2017 on fifth year (10-11) and sixth (12-13) primary school pupils in the state of Nuevo León (Mexico). The results indicated that the gender gap is not materially significant at this age, but there are already indications of what is observed in adultez. Multivariate analyses indicated that political socialisation and the consumption of social media contribute differently to the political knowledge of both genders. The politically converged environment improves girls’ political knowledge, while the consumption of political information via social media is decreasing. For both groups, socialisation at school has no effect at this age. The results of this study contribute to research on political knowledge in the Latin American context and recognises the political impact on citizens’ years of education. Practical implications of political and gender socialisation as well as the use of social media in the citizen development of boys and girls are discussed.