Lignin-modifying fungi are unique in their ability to degrade and modify aromatic lignin that is the most recalcitrant polymer present in plant cell walls. This is mostly due to their extracellular oxidative enzymes that catalyze unspecific reactions. In particular, class II heme peroxidases secreted by the basidiomycete white-rot fungi that inhabit wood and forest litter, are crucial in this process. In addition, enzymes that produce H₂O₂, a key metabolite in fungal plant biomass degradation, are essential e.g., for the heme peroxidase-catalyzed reactions. In this article, we provide an overview of the fungal lignin-modifying peroxidases and H₂O₂-producing enzymes, as well as potential applications of these enzymes in different fields of biotechnology.