Bullying is prevalent in many schools worldwide. Providing bullying prevention training to preservice teachers can make a significant difference in preventing school bullying. There is a lack of training in bullying prevention for preservice teachers in China, and the effectiveness of such training for bullying prevention has not yet been established. The present study examined the effectiveness of bullying prevention training on antibullying self‐efficacy and incorrect beliefs about bullying among Chinese preservice teachers. A total of 139 preservice teachers (Mage = 20.76 years, SD = 0.80 years, ranging from 19 to 23 years; 90.6% women) were randomly assigned to the bullying prevention training (n = 73) or the control group (n = 66). Preservice teachers completed pre‐ and posttraining surveys. The participants in the treatment group completed a 5‐week bullying prevention training program (1.5 h per week). Measures of antibullying self‐efficacy and incorrect beliefs about bullying were used to evaluate the effectiveness of the bullying prevention training. Results indicated that the training increased preservice teachers' antibullying self‐efficacy but did not decrease their incorrect beliefs about bullying. Practical implications, limitations, and future directions of these findings are discussed. Practitioner Points Bullying prevention training resulted in an increase of preservice teachers' antibullying self‐efficacy. The training did not decrease preservice teachers' incorrect beliefs about bullying. Incorporating bullying prevention training into the preservice teacher education curriculum is essential.