In geometry, the triaugmented truncated dodecahedron is one of the Johnson solids (). Of them, it has the greatest surface area and volume for a given side length, as well as the greatest numbers of edges and vertices; it is tied for the greatest number of faces with , , , and . As its name suggests, it is created by attaching three pentagonal cupolas () onto three nonadjacent decagonal faces of a truncated dodecahedron.