Time-of-arrival (TOA) estimation of OFDM signals in multipath channels is challenging, especially when the signal bandwidth is limited, such as is the case of WIFI. In this paper, a novel low complexity TOA estimation algorithm is developed for OFDM signals that is robust to various multipath environments. We approximate the received signal as Gaussian with a proposed autocorrelation model, and then derive the Maximum Likelihood estimator with an efficient implementation algorithm. The estimator performance was tested with off-theshelf WIFI 802.11g routers. The results show that the proposed TOA estimator outperforms other known reference methods over various indoor environments.