The use of animal-borne devices in wildlife ecology and conservation has expanded in recent decades. Animal-borne devices allow a suite of data to be collected, including locational, acoustic, and video. They have revolutionized our ability to collect measurements from animals and the environments that they inhabit, as well as promote the conservation of many species in their natural habitats. However, the use of these devices can also carry animal welfare, ethical, and privacy implications, device costs can limit the deployment of sufficient units, and the complexity of suitable analytical methods can limit inferences made. This chapter covers these topics by discussing how animal-borne devices, and particularly tracking technologies, are currently used in wildlife conservation and ecology. In particular, we discuss how and why animal-borne devices have advanced the study of wildlife, review key animal-borne devices in use today, and discuss the challenges and limitations of their use, as well as future opportunities, by drawing upon real-world examples from research and conservation.