Previous results show that Swedish upper secondary school teachers attribute gender to cases describing different types of mathematical reasoning. The purpose of this study was to investigate how these teachers gender stereotype aspects of students’ mathematical reasoning by studying the symbols that were attributed to boys and girls, respectively, in a written questionnaire. The results from the content analysis showed that girls were attributed gender symbols including insecurity, use of standard methods and imitative reasoning, and boys were assigned symbols such as multiple strategies especially on the calculator, guessing and chance-taking.