In this quasi-experimental study, we examined the effect of a self-reflection activity on the utility value of pre-service teachers in teaching game design. A pretest-posttest design was used to determine any differences associated with the intervention. 129 pre-service teachers from different majors participated in the study. The participants developed educational games using the MS Kodu game engine within a seven-week implementation process. The participants were randomly assigned to control and experimental groups before the intervention and engaged in specific interventions based on their group assignment. The control group students wrote summaries about game design activities, while the experimental group students wrote self-reflections about game design activities. The results indicated that the interventions influenced changes in the utility value of pre-service teachers: the utility value of the experimental group increased, while the utility value of the control group decreased. In addition, linguistic analyses indicated that students in the experimental group used more cognitive processing, affect, tentative language, and future focus than students in the control group. Gender differences in favour of female participants' utility-value perceptions were also observed following the game design process. This study provides empirical evidence of the effectiveness of self-reflection on utility value perceptions in teaching with game design.