Understanding the genetic basis of sheep tails is of great importance to improve sheep production and welfare. In this Comment, we discussed recent findings showing that homeobox B13 (HOXB13) is a regulator of the tail length in sheep. The revelation of the HOXB13 gene adds novel insights into the genetic determinism of the sheep tail phenotype. This new genetic highlight will lead to further advances in sheep breeding using selection-based strategies and molecular genetics-based tools.