To systematically review and integrate qualitative-research results pertaining to psychological distress in patients with breast cancer and to clarify its causes and drivers. Patients with breast cancer experience psychological distress in the stages of diagnosis, treatment, and rehabilitation, which seriously affects their quality of life. Through comprehensive qualitative research, the study comprehensively describes the experiences of patients with breast cancer to guide medical personnel in taking better care of them. A systematic review and synthesis of qualitative studies. Qualitative studies were included if they were related to the psychological-distress experiences of patients with breast cancer. The Joanna Briggs Institute Qualitative Assessment and Review Instrument was used to appraise study quality. Data were synthesised using the Thomas and Harden method of thematic and content analysis. Nine electronic databases (PubMed, Embase, Cochrane Library, CINAL [via EBSCO], and PsycINFO, China Knowledge Resource Integrated Database, Wanfang, Chinese Biomedical, and Weipu) were searched from inception until February 2024. Thirteen studies were included in the meta-synthesis. Four analytical themes were identified: diagnostic and therapeutic, individual, environmental, and interpersonal factors. Psychological distress is a subjective feeling influenced by interactions among individual, therapeutic, environmental, and interpersonal factors, and it is commonly encountered among patients with breast cancer. Therefore, to optimise the management of psychological distress, the characteristics and external environment of patients with breast cancer should be carefully considered when delivering routine nursing care. Patients experience psychological distress at different stages of breast cancer; however, the causes of psychological distress at different stages differ. Medical staff should implement targeted psychological-distress intervention measures based on factors relevant to different stages. The Enhancing Transparency in Reporting the Synthesis of Qualitative Research statement. The protocol of this study has been registered in the database PROSPERO (registration ID: CRD42023417364).