**1. Introduction**

Neutrophils are first responders of antimicrobial host defense and sterile inflammation, and therefore, play important roles during health and disease. Almost 16 years after the first description of neutrophil extracellular traps (NETs) as an alternative mode of pathogen killing, it has become clear that NETs also largely contribute to sterile forms of inflammation [1]. Indeed, NETs contribute to all forms of thrombosis, microparticle-induced inflammation, autoimmune vasculitis, auto-inflammatory disorders, and secondary inflammation due to ischemic, toxic, or traumatic tissue injury [1]. Recently, NETs have also been found to be an essential component of the multi-organ complications of COVID-19 [2].

In this Special Issue in *Cells*, we selected a series of articles that highlight the role of neutrophils and NETs in various sterile and non-sterile, acute and chronic inflammatory conditions affecting both human and animal health. We hope that this Special Issue will instigate novel research questions in the minds of our readers and will be instrumental in the further development of the field.
