The purpose of this study is to compare and analyze’ and teachers’ perceptions of problem behaviors in toddlers and children during the post-COVID-19 period. For this study, CBCL1.5-5, C-TRF data from 415 toddler’s and’ parents and teachers at 25 daycare centers located in Seoul were collected. The collected data were analyzed by SPSS 26.0. The results of this study are as follows. First, both parents and teachers perceive external problem behaviors at a higher frequency than internal problem behaviors of toddlers and children. Second, teachers perceive the level of all toddler’s and problem areas except physical symptoms higher than parents. Third, the agreement of parents’ and teachers’ evaluation was very low in all problem areas for the same infant. In conclusion, there is a significant difference in parents’ and teachers’ perceptions of problem behaviors in toddlers and children. Therefore, it is suggested that parents and teachers need to cooperate with each other and integrate the understanding of infant development for the healthy growth of toddlers and children.