The purpose of this study was to understand the effects of grandparenting on teenagers' school life adjustment. In this research, the questionnaires were used as an instrument and the participants were 390 junior and senior high school students. The analysis was done with independent sample t-test according to the school life adjustment scale. The study found that: In the aspect of learning adjustment in school life adjustment, the average of grandparenting teenagers (M=3.5692) was higher than the non-grandparenting teenagers (M=3.4120), and there was significant difference between the two groups (p<.05). The conclusion was that the grandparenting teenagers scored significantly higher than the non-grandparenting teenagers in the aspect of learning adjustment in school life adjustment.