The purpose of this study was to examine the effects of mixed reality simulations on preservice teachers' sense of self-efficacy. A quasi-experimental, one group with three levels, pretest-posttest 3 × 2 mixed design was used. Results showed a significant main effect for the between-subjects factor of total exposure (30, 60, or 90 minutes), as well as a significant interaction for the between-subjects and within-subjects factor of time (before, after). Implications for theory were that this study provided needed empirical data on the use of mixed reality simulations in teacher education with regard to self-efficacy and validated previous research. Implications on a programmatic level included that continued exposure within mixed reality simulations may develop teaching self-efficacy but that an initial drop in teaching self-efficacy occurring after 30 minutes of exposure to the simulations may warrant focused support.