A new species of Senna sect. Chamaefistula (DC. ex Colladon) H. S. Irwin & Barneby is described and illustrated under the name S. bracteosa D. Cardoso & L. P. Queiroz. This new species belongs to series Laxiflorae (Bentham) H. S. Irwin & Barneby and is related to S. lechriosperma H. S. Irwin & Barneby, both presenting a relatively wide pod (8–10 mm wide) and seeds transversely arranged inside the pod. It is distinguished from S. lechriosperma and from any other species of the series Laxiflorae by the lanate indument of the pod, larger bracts, larger flowers, the sepals densely tomentose, and the stamens glabrous. Senna bracteosa seems to be endemic to relictual hills surrounded by caatinga vegetation in the northeastern region of the state of Bahia, near the towns of Quijingue and Tucano, in eastern Brazil.