<span class="paragraphSection"><div class="boxTitle">Abstract</div>Herpesviruses are a group of double-stranded DNA viruses known to develop versatile viral strategies to escape host immune surveillance for promoting their replication and propagation. This is illustrated by Kaposi’s sarcoma-associated herpesvirus (KSHV), an oncogenic gamma-herpesvirus that overcomes host immune suppression by multiple mechanisms. In this study, we reported that KSHV dysregulates 5-methylcytosine (m5C) modification and messenger RNA (mRNA) stability of host antiviral factors to benefit its lytic replication. KSHV lytic reactivation or <span style="font-style: italic;">de novo</span> challenge led to downregulation of m5C RNA methyltransferases, NSUN2 and NSUN1 (NSUN2/1), while NSUN2/1 depletion promoted KSHV lytic replication. Such KSHV-mediated downregulation of NSUN2/1 is via suppression of the transcriptional factor c-Myc. We further performed the RNA bisulfite sequencing (RNA-BS-seq) to identify KSHV-dependent m5C modification of host mRNAs. KSHV lytic reactivation led to the significant reduction of m5C methylation and mRNA stability of TRIM25, a key activator of the RIG-I pathway, while TRIM25 depletion indeed promoted KSHV lytic replication. These host–virus interaction events were also observed in the infection of another oncogenic gamma-herpesvirus Epstein–Barr virus (EBV). Overall, our results highlighted a new strategy for human gamma-herpesviruses to counteract host antiviral factors and promote their lytic replication by manipulating host m5C RNA methylation.</span>