Objective: This study aims to identify the experiences and disease journeys of patients living with Triple-Negative Breast Cancer (TNBC) and healthcare professionals (physicians and nurses) regarding the diagnostic and treatment processes Method: A phenomenological research approach, a qualitative research model, was used. The participants consisted of 22 people, 10 women diagnosed with Triple-Negative breast cancer and 12 health professionals (7 physicians, 5 nurses). All interviews were audio-recorded and transcribed into written text. These texts and interviewer notes were analyzed using thematic analysis. Results: The analysis of the data revealed four main themes. The first theme, Diagnosis, highlighted that patients often consulted general surgeons due to palpable masses, experienced delays in diagnosis due to waiting for test results, the lack of consideration of cancer possibility in younger patients by physicians, and delays in seeking care due to misinformation. These delays, exacerbated by the aggressive nature of this cancer type, negatively impacted patients. The second theme, Treatment Process, identified differences in access to treatment between private and public healthcare institutions, the financial burden of treatments on patients, and the chemotherapy process as the most challenging period for patients. Issues such as hair, eyebrow, and eyelash loss had a negative effect on patients, and difficulties in accessing innovative medications were also reported. The third theme, Information, revealed that while physicians and nurses believed patients were sufficiently informed, many patients felt inadequately informed. Those who were negatively affected often sought information online. The fourth theme, Fertility or Fetus Preservation, showed that physicians attempted to be sensitive in this regard, but patients sometimes faced dilemmas between receiving treatment and preserving fertility or the fetus, leading to treatment delays. Conclusion: It can be stated that women living with Triple-Negative Breast Cancer (TNBC) experience a similar patient journey to those living with other types of breast cancer in terms of diagnosis access, utilization of treatment services, and information provision. In this context, difficulties in accessing diagnosis, treatments, and innovative therapies, challenges during the chemotherapy process, and inequalities between public and private healthcare services appear to be common issues in this journey for everyone. However, our study has shown that the presence of TNBC in younger women makes the effects of chemotherapy, such as hair loss, more pronounced, contributes to delays in diagnosis, and leads to issues related to fertility preservation. [ABSTRACT FROM AUTHOR]