Tracking the movement of insects in their natural habitat is essential for understanding their basic biology, demography, and ethology. A wide variety of markers have been used to assess insect population dynamics, dispersal, territoriality, feeding behavior, trophic-level interactions, and other ecological interactions. The ideal marker should persist without inhibiting the insect's "normal" biology. Furthermore, the marker should be environmentally safe, cost-effective, and easy to use. In this article, we review the current state of knowledge regarding insect marking, document the advantages and limitations of each marking technique, and discuss advances made in marking insects over the past decade.