Innate lymphoid cells (ILCs) communicate with other hematopoietic and nonhematopoietic cells to regulate immunity, inflammation and tissue homeostasis. How ILC lineages develop and are maintained remains largely unknown. In this study we observed that a divergent long noncoding RNA (lncRNA), lncKdm2b, was expressed at high levels in intestinal group 3 ILCs (ILC3s). LncKdm2b deficiency in the hematopoietic system led to reductions in the number and effector functions of ILC3s. LncKdm2b expression sustained the maintenance of ILC3s by promoting their proliferation through activation of the transcription factor Zfp292. Mechanistically, lncKdm2b recruited the chromatin organizer Satb1 and the nuclear remodeling factor (NURF) complex onto the Zfp292 promoter to initiate its transcription. Deletion of Zfp292 or Bptf also abrogated the maintenance of ILC3s, leading to susceptibility to bacterial infection. Therefore, our findings reveal that lncRNAs may represent an additional layer of regulation of ILC development and function.