Gold nanoparticles have emerged as a promising material for biomedical research due to ease of synthesis and highly adjustable optical properties, which can be utilized in the imaging of different diseases. Gold nanoparticles are fabricated by grafting biocompatible polymers and natural or synthethic biomolecules and present a novel avenue for engineering multifunctional smart systems. Many reports on the significant achievements and the bioconjugation chemistry promise to expand the application spectrum of gold nanoparticles. This review summarizes the current state-of-the-art development of functionalized gold nanoparticles for cancer gene therapy.