A new species, Sedum brachetii Reyes, Islas et González-Zorzano, is described from Guerrero, Mexico. Placed within the section Pachysedum, S. brachetii differs from its closest comparable relatives S. clavatum, S. orbatum, S. cuspidatum and S. ocuilense in stem size, leaf structure, inflorescence size and nectary color. Figures of the holotype are provided.