Recent educational policies, national reports, and voluminous literature stress that critical thinking (CT) is an essential skill in any stage of schooling for producing critical thinkers and ensuring better learning. The importance of teaching CT has been raised in teacher education programmes because students are supposed to teach this skill in schools in the future. This study therefore assesses the effects of a CT-based pedagogical course on student teachers' content knowledge and CT disposition. A pre-test-post-test experimental study was carried out in a vocational pre-service teacher education programme in Turkey. Although the students who were exposed to CT-based instruction showed better progress in both academic achievement and CT disposition than in traditional instruction, this result was not statistically significant according to the Mixed Factorial ANOVA and ANCOVA results.