We know that, a polyhedron is a 3D shape that has flat surfaces. Hence, a regular polyhedron is a polyhedron having regular flat surfaces or congruent flat surfaces.
In a cube, all the surfaces are flat and squares which are all congruent.
Hence, a cube is a regular polyhedron.
However, in a cuboid, we have rectangular flat surfaces which are not congruent.
Hence, a cuboid is not a regular polyhedron.
Hence, the given statement is true.