Since the 1990s, fathers’ use of parental leave has become commonplace, normalised, and expected, especially in the Nordic countries, which were the first to introduce earmarked periods of paid leave for fathers. This development has given rise to a research field that is explored and conceptualised in this systematic literature review as gender research on fathers’ parental leave experiences of primary childcare. The aim is to identify and critically discuss salient gender theory approaches within this research field. The materials comprise 26 publications analysed using a thematic and retroductive method. Three salient gender theory approaches are identified and discussed: ‘the empirically situated gender theory approach,’ ‘the multilevel gender theory approach,’ and ‘the masculinity theory approach.’ To avoid theoretical homogenisation and a reified understanding of the notion of masculinities, I suggest that emerging gender theory approaches in the field of gender research on fathers’ parental leave experiences need to be developed – in dialogue with feminist fatherhood research, CSMM, and childhood studies. Firstly, there is a need to theorise themes positioned as empirical ‘findings’. Secondly, a deliberate child perspective is needed. Finally, gender theory approaches need to overcome the ‘either/or’ situation, in which the analyses are either empirically grounded or theoretically informed.