In geometry, an icosidodecahedron is a Polyhedron with twenty triangular faces and twelve pentagonal faces. It has 30 identical vertices, with two triangles and two pentagons meeting at each, and 60 identical edges, each separating a triangle from a pentagon.

Its Dual polyhedron is the Rhombic Triacontahedron. An icosidodecahedron can be split along any of six planes to form a pair of pentagonal rotundae, which is one of the Johnson solids.