We demonstrate that the resonances of infrared plasmonic antennas can be tuned or switched on/off by taking advantage of the thermally driven insulator-to-metal phase transition in vanadium dioxide (VO₂). Y-shaped antennas were fabricated on a 180 nm film of VO₂ deposited on a sapphire substrate, and their resonances were shown to depend on the temperature of the VO₂ film in proximity of its phase transition, in good agreement with full-wave simulations. We achieved tunability of the resonance wavelength of approximately 10% (>1 μm at λ∼10 μm).