Localised surface plasmon resonance endows plasmonic nanostructures with unique, powerful properties such as photoluminescence enhancement, which is a phenomenon based on the interaction between light and a metal nanostructure. In particular, photoluminescence modulation and enhancement are of importance to many research fields such as photonics, plasmonics and biosensing. In this minireview, we introduce basic principles of plasmonic-nanostructure photoluminescence and recently reported plasmonic nanostructures exhibiting surface-enhanced fluorescence and direct photoluminescence, with one-photon photoluminescence being of particular interest. Gaining insights into these systems not only helps understand the fundamental concepts of plasmonic nanostructures but also advances and extends their applications.