Plants are exposed to a plethora of disease-causing agents like bacteria, fungi, viruses, and nematodes in their natural habitat. To counteract the harmful effects of these phytopathogens, plants have developed certain mechanisms where they stimulate or suppress a diverse array of genes. Among these, are the plant microRNAs (miRNAs), which are small regulatory RNAs, responsible for gene silencing in plants. These miRNAs play vital roles in developing resistance against phytopathogens by suppressing various genes at the post-transcriptional levels. The alterations in the expression levels, both of genes and miRNAs, mediate defense responses in plants and are also involved in managing resistances in plants in response to different stresses. Lately, high-throughput sequencing has led researchers to identify and characterize several miRNAs in plants and their involvement during pathogen invasion. Hence, the current book chapter highlights the recent advances and mechanisms that are involved in the defense responses of plant miRNAs against various phytopathogenic organisms.