RNA interference (RNAi) is a highly conserved intracellular regulatory phenomenon in plants to regulate gene expression by either suppressing transcription or degrading the mRNA. The well-documented harmful effects of chemicals like pesticides on human and animal health have driven researchers to investigate RNAi as a promising biotechnological approach. This strategy aims to tackle the significant problem of crop damage caused by biotic stressors, which are major obstacles to achieving global food security. The mechanism of RNAi consists of three major components: the inducer (dsRNA), the messenger RNA, and the set of proteins that initiate the degradative process, which are comparable in ancestry across most organisms. Transgene-induced RNAi has demonstrated efficacy in gene suppression across numerous plant species, presenting significant potential as a tool for functional genomics in various taxa. The capacity to modify the expression of a specific transcript enables the precise association of an individual gene with its consequent phenotypic effects, which are absent in non-transgenic plants. Since its development, RNAi has become a valuable tool for gene silencing in various domains of biological research. In recent years, the application of this mechanism in plant protection has significantly increased. Utilizing this approach in plants for antiviral defense is highly effective, as it suppresses viral transcripts in plants which enhances the plants’ innate or engineered resistance to viruses. When a virus attacks, RNA viruses produce double-stranded (ds) RNA molecules through activation or as replication intermediates, which trigger the host’s RNAi defense mechanism. This leads to the specific degradation of viral RNAs, thereby inhibiting viral expression. This chapter delves into the detailed applications and mechanisms of RNAi in managing viral diseases in plants.