BackgroundMolecular genetics serve a critical role in constructing risk stratification for hematological malignancies, but T‐cell lymphoma (TCL) still lacks molecular genetic information for supplement risk stratification in predicting the prognosis of TCL patients. In the present study, we characterized the mutation patterns of B‐cell leukemia/lymphoma 11B gene (BCL11B) and its prognostic importance in TCL patients.MethodsBCL11B mutations were characterized based on the data from two datasets, one is from our clinical center (GDPH dataset, n = 79) and the other is from COSMIC dataset (n = 154).ResultsThe overall mutation rate of BCL11B was 6.4% (15/233) in TCL, and there were no hotspot mutation sites in TCL. Among these mutations, the missense and splice site mutation were significantly prominent. Moreover, TCL patients harboring BCL11B mutations had a favorable overall survival (OS) in our center (GDPH dataset) (adjusted hazard ratio [HR] = .001, p = 0.109), although there were not yet significantly statistical at this point. In addition, TCL patients harboring BCL11B mutation had a longer 5‐year restricted mean survival time (RMST) than those without a BCL11B mutation (60 vs. 32 months). Notably, BCL11B mutations were not associated with TCL entities having better prognosis.ConclusionsBCL11B mutations were associated with favorable clinical outcome for TCL patients; it might be considered as a novel biomarker for TCL prognostic stratification.