Entomopathogenic fungi (EPF) and entomopathogenic nematodes (EPNs) have a strategic and important role in the biological control of agrophages. Micro- and macro-organisms have become an alternative to chemical methods, not only reducing the use of chemical pesticides, but also preventing agrophages from becoming resistant to chemicals and minimizing risks to human, animal and environmental health. The common habitat of EPNs and EPF is the soil, but interactions between them have mainly been studied in the laboratory. Recently, there has been a growing interest in combining biological control agents to increase their efficacy, and many studies have focused on combining EPF and EPNs against different insect pests. Studies have shown synergistic, additive or antagonistic effects. The results of these interactions depend on the pathogen, the host species, the different times of infection and the choice of the appropriate pathogen dose. The aim of this review was to summarize the existing knowledge on the life cycle of nematodes and the mechanisms of action of EPF and their application in practice, as well as the interaction between EPNs and EPF in plant protection against insect pests.