The ambition of the article is to create an awareness among upper secondary school pupils on what academic integrity and source criticism mean. Instead of devoting time to a general presentation of academic studies, the claim is that a collective reflection based upon the common practices of pupils (sources) could be efficient to describe the outlines of academic integrity. An action research was made in 2019 and 2020 among Swedish upper secondary school pupils with the help of an instructional video on sources, academic integrity and plagiarism. It revealed a consensus on the notion of source criticism. Furthermore, the findings show that a majority of pupils used platforms such as Wikipedia to get a quick access to facts without daring quoting them in a work for school. This gap represents an opportunity to introduce academic integrity in a very concrete manner with an insistence on the necessity of citing all the sources that contributed to the elaboration of a work.