Activated neutrophils can undergo a mode of regulated cell death, called NETosis, that results in the extrusion of chromatin into the extracellular space, thereby acting as extracellular traps for microorganisms. Neutrophil‐derived extracellular traps (NETs) are comprised of DNA decorated with histones, antimicrobial proteins and neutrophil granule proteases, such as elastase and cathepsin G (Cat G). NET‐associated factors are thought to enhance the antimicrobial properties of these structures and localisation of antimicrobial molecules on NETs may serve to increase their local concentration. Because neutrophil‐derived proteases have been implicated in the processing and activation of several members of the extended interleukin (IL)‐1 family, we wondered whether neutrophil NETs could also serve as platforms for the activation of proinflammatory cytokines. Here, we show that neutrophil NETs potently processed and activated IL‐1α as well as IL‐36 subfamily cytokines through NET‐associated Cat G and elastase. Thus, in addition to their role as antimicrobial traps, NETs can also act as local sites of cytokine processing and activation.