This study is to explore the meaning of the mother's experience in self-determination support for adult child with mild intellectual disabilities. Participants in the study are Kim So-ri (pseudonym), a mother of adult children with mild intellectual disabilities, and the data collection period is from August 2022 to November 2023. The collected data were analyzed in a three-dimensional narrative inquiry space considering time, sociality, and place. The results of the study were meaningful as first, controlling anxiety and setting boundaries, going out to hope, and second, seeking social help against social prejudice, and third, finding independent lives with children. It is expected that the stories of participants in this study will be used to support mothers with intellectual disabilities in psychological counseling or to support them in the treatment field.