PURPOSE: As the prognosis for adolescents and young adults (AYAs) with breast cancer has improved, long-term health-related quality of life (HRQoL) has become increasingly important. This study aimed to analyze the long-term HRQoL of AYA breast cancer survivors compared to an age-matched normative population and to identify factors associated with HRQoL. METHODS: Secondary analyses were conducted using data from the SURVAYA study. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core-30 (EORTC QLQ-C30) was used to assess HRQoL. The Mann-Whitney U test was used to compare HRQoL scores of AYA breast cancer survivors with those of the normative population (n = 409). Linear regression models were constructed to identify patient and treatment characteristics associated with HRQoL. RESULTS: A total of 944 female AYA breast cancer survivors were included, with a median age of 36.0 years and a median follow-up of 12.2 years. AYA breast cancer survivors scored significantly lower on five functional scales: physical, role, emotional, cognitive, and social, and higher on five symptom scales: fatigue, pain, dyspnea, insomnia, and financial impact compared to the normative population. Being in a relationship, having a positive body image, and adaptive coping were positively associated with HRQoL, while older age, chemotherapy, unemployment, and maladaptive coping were negatively associated. CONCLUSION: AYA breast cancer survivors experience significantly compromised long-term HRQoL compared to an age-matched normative population. These results highlight the need for tailored follow-up care and long-term support, as well as the importance of shared decision-making about the benefits and risks of treatments before initiation.