Swedish studies concerning children’s reading habits show that detective stories have become more popular in recent years. The aim of this bachelor’s thesis is to examine how the gender system is described in four detective stories written for children at the age of 9 to 13 years. Our main question is: How is the gender system reflected in the four selected detective stories for children? We also pose the question: How are femininity and masculinity described? Our study is based on three theories. First, Yvonne Hirdman’s theory about the gender system, primarily the two basic principles: the logic of the separation of the sexes, the dichotomy, and the logic of the male norm, the hierarchy. Secondly, the theory that claims literature to be a reflection of society, presented by the Sociology of Literature. And finally, Maria Nikolajeva’s theory that the sexes are described as opposites in literature. Our used method is text analysis. We have constructed several analysing questions that we have applied to the texts. Our results are not unambiguous; we can observe a lot of stereotype gender patterns but also more equal descriptions when it comes to the dichotomy, the hierarchy and the descriptions of femininity and masculinity. A conclusion that might be drawn is that literature is a reflection of the society where the consciousness of gender issues has increased.