Dendrimers are highly branched organic macromolecules with successive layers of branch units surrounding a central core. Some properties like toxicity, entropy, and heats of vaporization of these dendrimers can be forecasted using topological indices. e present article is devoted to study of irregularity indices of three well-known classes of dendrimers, namely, nanostar dendrimer D [p], fullerene dendrimer NS 4 [p], and polymer dendrimerNS 5 [p], where p is the step size. We also see the relation of irregularity of these dendrimers on the step size graphically.