Many adolescents with type 1 diabetes experience challenges in achieving good glycemic control and have insufficient understanding in executing interventions for glycemic control. This study aimed to understand self-management experiences of adolescents with type 1 diabetes in Taiwan. In this descriptive phenomenological study, we conducted in-depth interviews with 18 adolescents with type 1 diabetes from the pediatric outpatient clinic of a medical center. Data were analyzed using the Colaizzi’s method. Four themes were identified: (1) misconception regarding self-management of blood glucose; (2) conflict between depending on and breaking away from parental assistance for glycemic control; (3) encounter with disruptions in glycemic control regimen due to the presence of schedule changes; and (4) lack of motivation to achieve good glycemic control. The findings indicated that the misconceptions of adolescents with type 1 diabetes about managing glycemic levels resulted from an insufficient understanding of self-management of diabetes. In Taiwan, the heavy emphasis of academic achievement and changes of schedules during breaks tended to disrupt the regimen for glycemic control. Healthcare professionals are encouraged to provide individualized education focusing on the adolescents’ misconceptions regarding self-management of diabetes.