The subclass Copepoda is one of the most important animal groups in aquatic ecosystems. Ecologists, evolutionary biologists, and biotechnologists are continuously trying new approaches for the study of copepods as model organisms for a wide variety of fields in pure and applied science, from evolution and ecology, to their utilization as live feed for aquaculture, as biological control of mosquito larvae, and as bioindicators of water and sediment quality for environmental monitoring, and as a source of protein in local populations. Here we summarize some of the advances and trends in the study of copepods from different approaches. This article highlights the importance of copepods and the need to enhance and intensify the research on various topics related to copepods, some of them for local sustainable development.