The purpose of this research was to investigate the effect of simulation-supported inquiry-based learning on pre-service teachers' conceptual understanding of capacitors. The participants consisted of 50 pre-service teachers studying at a state university in Turkey. The participants were divided into two groups of 25 each on the basis of their physics grades in the previous semester. The research was patterned according to a non-equivalent control group design with pretest and posttest. The experimental group used simulation-supported inquiry-based learning, and the control group used lecture-based learning supported by simulations. The research data were collected with the Capacitor Concept Test prepared by the researchers. The findings showed that pre-service teachers had various misconceptions about parallel plate capacitors before the implementation. The research revealed that inquiry-based learning was more effective than lecture-based learning in eliminating these misconceptions.