The present disclosure is directed to tip extensions for wind turbine rotor blades and methods of installing same. The method includes removing a removable blade tip of a lightning protection system from the rotor blade so as to expose a down conductor of the lightning protection system. The method also includes securing a conductive extension to the down conductor. Moreover, the method includes sliding the first end of the tip extension over the conductive extension so as to overlap the rotor blade at the tip end. In addition, the method includes securing the removable blade tip to the conductive extension at the second end of the tip extension. Further, the method includes securing the tip extension to the rotor blade.