The cellulose synthase (CesA) and cellulose synthase-like (Csl) superfamily encodes critical enzymes involved in processing plant cellulose and hemicellulosic polysaccharides. The alfalfa (Medicago sativa L.) genome was sequenced in recent years, but this superfamily remains poorly understood at the genome-wide level. We identified 37 members of the CesA/Csl family from the alfalfa genome in this study as well as their chromosomal locations and synteny. We uncovered 28 CesA/Csl expressed across all tissues and CslD genes specifically expressed in the root. In addition, cis-acting element analysis showed that CesA/Csl contained several abiotic stress-related elements. Moreover, transcriptomic analysis of alfalfa seedlings demonstrated the involvement of this superfamily in responses to cold, drought, and salt stresses. Specifically, CslD increased expression in cold conditions and decreased under osmotic stress, highlighting its potential role in stress adaptation. The findings offer valuable information for the practical exploration of the functions of CesA/Csl during plant development and the development of enhanced tolerance to different stress conditions.