Tantrums are excessive emotional outbursts by a person when his desires are not fulfilled, especially in preschool children. This can happen because of the immediate environment and the parenting style. This study aims to figure out the effect of Parent Management Training (PMT) on increasing maternal knowledge of dealing with tantrums in preschool children. This study was conducted on parents aged 25–40 who had children aged 3-5 years. This is experimental research with a one-group pretest-posttest design. The training instruments used were the PMT module and worksheet. Meanwhile, the data were collected using tests, observations, interviews, and Focus Group Discussion (FGD) which refers to the tantrum behavior scale. The data was then analyzed using two related sample tests with Wilcoxon tests assisted by SPSS 22 software. The results showed that the value of Z was -2.803 with a significant test value (p) (Asymp. Sig. 2 tailed) of 0.00, which was less than 0.05 (p<0.05). Accordingly, the research hypothesis is accepted. Thus, PMT has a significant influence on reducing tantrum behavior in preschool children.