This correlational study aims at exploring the correlations between symptom burden, functional status, and self‐efficacy in advanced breast cancer patients and to analyze their paths of influence. The study was performed with 122 patients with advanced breast cancer receiving outpatient chemotherapy between April 10, 2021 and April 29, 2022. Data were collected using a sociodemographic information form, the MD Anderson Symptom Inventory, the Functional Living Index‐Cancer, and the Symptom Management Self‐Efficacy Scale for Breast Cancer Related to Chemotherapy. Kruskal–Wallis, Mann–Whitney U, and Spearman correlation tests and path analysis were used for data evaluation. Less‐educated individuals had a higher symptom burden and poorer self‐efficacy. Low‐income level was related to poor self‐efficacy. Symptom severity did not directly influence functional status but affected it indirectly through self‐efficacy, while symptom interference and self‐efficacy had a direct impact on functional status. This study mainly concludes that symptom burden and self‐efficacy affect functional status in advanced breast cancer patients receiving chemotherapy. Self‐efficacy‐enhancing interventions may be helpful strategies for symptom relief and improvement in functional status in this population.