A mindset training aims to strengthen the belief that abilities are malleable (growth mindset), which has proven to be beneficial for learning. Teachers can support the effects of such a training by establishing a classroom culture in line with the growth mindset idea. Yet, previous training programs have mostly been detached from regular lessons. In this study, a physics teacher implemented a mindset training that consisted of explicit training sessions and implicit training phases. In these implicit phases, the teacher enriched ordinary lessons with growth mindset feedback. We investigated the overall effect of this lesson-integrated training on students’ beliefs and motivation. Students from two seventh-grade courses participated in the ...