The development of advanced materials from inorganic nanoparticles (NPs) is currently one of the most dynamic areas of science. NPs are attracting significant fundamental and commercial interest, with a wide range of applications including the next generation of optics, electronics, and sensors. In optical, electrical, and magnetic devices, NPs will be mostly used in the form of thin films. Currently, such films are typically made by the spincoating, spraying, or sometimes simple painting of nanoparticle–matrix mixtures. Layer-by-layer (LBL) assembly is one of the new methods of thin-film deposition, often realized as sequentially adsorbed (mono)layers of oppositely charged polyelectrolytes. LBL assembly has also been successfully applied to thin films of NPs and nanocolloids, that is, dispersed species with only one or two spatial dimensions in the nanoscale regime.