Background: The aim of this study is to evaluate the outcomes and prognostic factors in patients with hepatocellular carcinoma (HCC) and Child–Turcotte–Pugh (CTP) class B liver function after stereotactic ablative radiotherapy (SABR). Materials and Methods: This retrospective study evaluated patients with HCC and impaired liver function who underwent SABR between December 2007 and August 2016. All patients had CTP class B liver function before treatment. Local control (LC) rate, overall survival (OS) rate, prognostic factors, and radiation‑related toxicity were evaluated. Results: This study included 34 patients. The majority had a CTP score of B7 (52.9%) and advanced HCC (91.2%). The median survival time was 4.8 months, and the 1‑year OS rate was 21.4%. Only the tumor number (multiple vs. single) was identified as an independent predictor of survival. The 1‑year LC rate was 95.8%. Eight patients (23.5%) developed the radiation‑induced liver disease, and 15 (44.1%) had a CTP score decline of ≥2 within 3 months. Other toxicities were generally tolerable. Conclusion: SABR may be considered as an alternative option for patients with HCC and CTP class B liver function, particularly for those with a single lesion.