The effects of polyacrylamide (PAM) as a capping agent, and zirconium as a dopant, on the structural and optical properties of ZnO nanoparticles were investigated. All the samples were prepared by microwave irradiation in an aqueous system without a post-annealing step. The crystallite sizes were decreased by the incorporation of Zr and PAM. The photoluminescence efficiency was enhanced for samples with PAM-capped ZnO and PAM-capped ZnO doped with Zr, when compared to the pure ZnO. The broad visible luminescence signified the suitability of these nanoparticles as a white phosphor.