A highly efficient 2.4 GHz rectenna is designed using a harmonic rejection bandpass filter. The rectenna is printed on Rogers Duroid 5880 substrate with ${varepsilon}_r$=2.2 and a thickness of 1.6 mm. The rectenna consists of a microstrip antenna and high order harmonic rejection bandpass filter, microstrip lowpass filter, and Schottky barrier diode (HSMS2820). The use of a $2^{nd}$ and $3^{rd}$ harmonic rejection microstrip bandpass filter in the rectenna results in high conversion efficiency. The proposed rectenna achieves a RF to DC conversion efficiency of 72.17 % when the received RF power is 63.09 mW.