This document analyzes the performance of M-QAM modulation in OFDM systems. It begins with an introduction to OFDM and how it addresses issues like intersymbol interference caused by multipath fading. It then describes M-QAM and M-PSK modulation schemes used in OFDM. Through MATLAB simulations, it evaluates the bit error rate performance of different modulation orders in AWGN and frequency selective Rayleigh fading channels. The results show that higher order QAM in OFDM provides better performance with lower bit error rates than PSK, especially at higher SNR values. Therefore, QAM is determined to be a better choice than PSK for high data rate transmission using OFDM.