The purpose of this article is to shed light on the ways in which World War II ideologically interacted with education and social networks within a school context, on the basis of a pupil’s diary. More specifically, this paper looks at pupils’ active involvement in contesting the patriotic school climate and deals with the effects of what happens when the predominant school’s belief or value system is questioned ‘from below’.The paper presents a case-study of ideological conflict in a Flemish school, the Sint-Jozefscollege in Turnhout, during the second half of 1940. It is primarily based on the diary of one pupil. I argue that the diary can reveal the ways in which the war did or did not penetrate language and daily school life and that this type of research enables us to grasp the many complexities of past society, or even, to some extent, offers a corrective for the ‘grand narrative’ of both educational and World War II history, which unavoidably present some generalisations. This article suggests that this grand narrative could benefit from the confrontation with personal documents that focus more on private interpretations of these big events. As a result of the prevalent use of ‘traditional’ written sources in historiography, the history of war-time schooling ‘at the chalk face’ in large part remains virgin territory. The diary is one of few sources that leave us with an idea of pupils’ experiences in the period under review.