The behavioral ecology of entomopathogenic nematodes (EPNs) has been studied in several different contexts. Starting in the 1980s, studies of foraging behavior and infection behavior were conducted with the objective of determining how to use EPNs effectively and concentrated on narrowing the gap between laboratory results and field results. This emphasis remains. But as research questions grew more complicated and methods more sophisticated, EPNs began to emerge as model systems to study various theoretical underpinnings of animal behavior. Here, we address primarily the results of studies that can be used to improve the biocontrol potential of EPNs, for example studies of how EPNs behave when in contact with different substrates, or infection dynamics. We also attempt to link infective juvenile (IJ) behavior with field distributions. This work is applicable to explain what happens to IJs after application, for example. We also touch on studies that do not address biocontrol directly, such as male–male conflict within infected cadavers. Finally, we review recent work that goes past documenting and understanding EPN behavioral ecology and seeks to use what has been learned to manipulate these behaviors to benefit biological control outcomes. Early studies on EPN behavior sought to discover what IJs did in response to putative hosts. The next step was to build on these studies to improve our predictive capabilities about when and where EPNs would be successful biological control agents. Most recently, the work transcends understanding and predicting behaviors to actually changing EPN behavior to improve their effectiveness.