This study aimed to investigate the effects of augmented reality (AR) activities on students' academic achievement and motivation in a biology course. For this purpose, a mixed study was conducted, and a pretest and posttest control group model was used. In addition, the opinions of the experimental group students and the teacher about the AR activities were taken, and classroom observations were made during the study. The study group consisted of 40 (22 female and 18 male) ninth-grade biology course students. The control group followed the biology course programme, whereas the experimental group students conducted AR activities in addition to the course programme using tablets. Consequently, it was found that the motivation of the students in the experimental group increased more than that of the students in the control group. However, no significant difference was found between the academic achievement scores of the groups. The teacher and the students stated that AR activities might be effective in increasing course success and motivation.