RNA silencing suppressors, developed by plant viruses, are potent arms in the arm race between plant and invading viruses. In higher plants, these proteins efficiently inhibit RNA silencing, which has evolved to defend plants against viral infection in addition to regulation of gene expression for growth and development Virus-encoded RNA-silencing suppressors interfere with various steps of the different silencing pathways and the mechanisms of suppression are being progressively unraveled. Our better understanding of action of silencing suppressors at molecular level dramatically improved our basic knowledge about the intimate plant-virus interactions and also provided valuable tools to unravel the diversity, regulation, and evolution of RNA-silencing pathways.