In the study presented in this article, the aim is to further the understanding regarding the differences between pupils (aged 15-16) from schools with low or high socio-economic status (SES), regarding the amount and diversity of content knowledge in history that they have acquired by the end of compulsory schooling. Following a definition of historical content knowledge, we situate the concept in relation to other aspects of the history school subject. This is done to visualize historical content knowledge's central role in more complex aspects of the subject. The empirical material used in the study is pupils' responses on both selected and constructed response items on the Swedish national test in history. In the study, a combination of qualitative and quantitative approaches is used. The results show not only that pupils in low-SES schools provide fewer examples of historical content knowledge. We can also establish that the historical content knowledge of pupils from high-SES schools represents several perspectives while there are few perspectives present in the responses from pupils in low-SES schools. The results are used to discuss how the differences between pupils in low- and high-SES schools may affect their possibilities for educational success and active participation in society.