This study aimed to investigate the effects of augmented reality (AR) applications in geometry teaching on academic achievement, self-regulated learning skills (SRLS), and motivation of secondary school students. The research was carried out on students in the eighth grade at a state secondary school in Turkey. The research was carried out according to the quasi-experimental design with the pretest-posttest control group, including 20 students in the experimental group (EG) and 20 in the control group (CG). While geometry teaching supported by AR applications was carried out with the EG students, traditional education was carried out with the CG students. Within the scope of the mathematics course, the achievements of the three-dimensional geometric objects unit in the curriculum were discussed. As a result of the analysis, it was determined that the difference in achievement test, self-regulated learning scale, and motivation scale scores between the groups was statistically significant in favor of the EG students. The study's qualitative findings show that the AR application is fun and interesting for the students and positively affects academic achievement and active participation in the lesson. The research results were discussed according to the results in the literature, and suggestions were made for new research and applications.