Objectives The purpose of this study was to examine the moral judgment, differences in the concept of forgiveness, and the developmental stage of the concept of forgiveness according to the age of children aged 3 to 5. Methods Data were collected using video records (VTR) and interviews containing moral judgments and forgiveness concepts for 46 people aged 3 to 5 who are enrolled in kindergartens affiliated with universities in Gyeonggi-do. Descriptive statistics, frequency analysis, and chi-square test were performed on the collected data using SPSS 23.0. Results First, the moral judgment of children aged 3 to 5 differed according to age. Second, there was an age difference in the concept of forgiveness of children aged 3 to 5 in terms of whether or not to play together, which is a sub-factor. Third, the development stage of the concept of forgiveness in children aged 3 to 5 was no age difference in the developmental, children are mainly found to be a second stage of restitutional forgiveness. Conclusions This study verified age differences in children's moral judgment and forgiveness concepts. It is meaningful in that it provides implications and educational directions for forgiveness education to parents and teachers.