Objective:The purpose of this study was to investigate trajectories of child peer interaction and to compare the causal effects of their predictors, including child individual variables (i.e., gender, language ability, and cognitive ability) and teacher variables (i.e., teacher efficacy and teacherchild interaction). Results and Conclusion: The findings of this study are as follows: First, there was a linear decrease in child negative peer interaction over the course of 3 years, and significant individual differences were found in the trajectories (intercept and slope). Second, the predictors had significant casual effects on the trajectories of child negative peer interaction. The trajectories of child negative peer interaction involving girls, higher cognitive ability, and greater teacher-child interaction showed lower degree of intercept and a quicker decrease. Finally, the implications of findings are discussed.