Studies on Southeast Asian literature often consider literary works as allegories for the economic, political, cultural, and social issues of Southeast Asian countries and pay little attention to children’s literature in this region. The article uses the juxtapositional model of comparison to examine three beautiful pieces of work of Southeast Asian children’s literature, including Chai thời gian [Bottle of Time] by Prabhassorn Sevikul (Thailand), Tôi thấy hoa vàng trên cỏ xanh [I See Yellow Flowers in the Green Grass] by Nguyễn Nhật Ánh (Vietnam), and Chiến binh Cầu Vồng [The Rainbow’s Troops] by Andrea Hirata (Indonesia). The article focuses on clarifying the difficult transition to adulthood of the child characters in these three pieces and how the characters face events to improve themselves and find meaningful things in life. It also proposes another concept of the age from 12-13 years old to before 18 years old to emphasize the meaning of transition associated with changes in the physical, mental, and cognitive of children at this age.