Plant viral diseases result in significant agricultural losses globally. Unlike fungal or bacterial plant pathogens, viruses cannot be directly managed by chemicals. Their management mostly reliant on controlling insect vectors and breeding for host resistance. However, plants possess intrinsic molecular defense mechanisms that limit viral infections. RNA silencing pathways, particularly post-transcriptional gene silencing (PTGS) driven by small RNAs, play a crucial role in antiviral defense. Other epigenetic mechanisms, including RNA-directed DNA methylation (RdDM), N6-methyladenosine (m6A) RNA modifications, histone modifications and chromatin remodeling, also contribute to gene regulation during viral infection. DNA methylation patterns can be inherited across generations in a stable way, potentially conferring viral resistance to next generations. Virus-derived 24-nt small interfering RNAs (siRNAs) can function as mobile epigenetic signals, capable of inducing systemic gene silencing. A deeper understanding of epigenetic gene silencing mechanisms in virus-infected plants could improve biotechnological approaches for virus diagnosis, pathogenesis research and disease management. This review summarizes current insights into plant epigenetic gene silencing and explores their potential applications in the development of an antiviral defense system.