This paper proposes a new detection algorithm called particular swarm optimisation (PSO)-based discrete wavelet transform (DWT) for multiple-input-multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) system. In all previous studies, PSO detection algorithm and DWT were separately proposed for MIMO-OFDM systems. Motivated by the performances enhancement achieved by these techniques, PSO is combined to DWT transform in this work for symbol detection in MIMO-OFDM system. The simulation results show that the proposed PSO-based DWT MIMO-OFDM system boosts the performances of zeros forcing (ZF), minimum mean square error (MMSE), and even PSO-based FFT MIMO-OFDM equaliser. The proposed detector presents near optimal performances in terms of bit error rate (BER) and a significant computational complexity reduction for different constellation diagram and number of transmitting antennas compared to maximum likelihood (ML) detector.