High-throughput sequencing of taxon-specific loci, or DNA metabarcoding, has become an invaluable tool for investigating the composition of plant-associated fungal communities and for elucidating plant–fungal interactions. While sequencing fungal communities has become routine, there remain numerous potential sources of systematic error that can introduce biases and compromise metabarcoding data. This chapter presents a protocol for DNA metabarcoding of the leaf mycobiome based on current best practices to minimize errors through careful laboratory practices and validation.