B-cell lymphoma/leukemia 11B is a protein that in humans is encoded by the BCL11B gene.

This gene encodes a C2H2-type zinc finger protein and is closely related to BCL11A, a gene whose translocation may be associated with B-cell malignancies. The specific function of this gene has not yet been determined. Two alternatively spliced transcript variants, which encode distinct isoforms, have been reported. [provided by RefSeq].
Function: Tumor-suppressor protein involved in T-cell lymphomas. May function on the P53-signaling pathway. May be a key regulator of both differentiation and survival during thymocyte development. Repress transcription through direct, TFCOUP2-independent binding to a GC-rich response element (By similarity).