To address the flaws of limited modulation bandwidth and frequency-selective fading, a visible light communication system, which is based on three-dimensional orthogonal frequency division multiplexing (3D-OFDM), has thus been proposed. On the basis of three-dimensional constellation mapping, the system helps to increase the minimum Euclidean distance (MED) between adjacent constellation points, thereby reducing the bit error rate of the system. A three-dimensional constellation mapping method, which is based on K-means clustering demodulation, is proposed for a solution of hard decision demodulation at the receiver being susceptible to nonlinear effects in visible light channels and sampling frequency offset interference. The results show that at a bit error rate of 3.8e-3, compared to 2D-OFDM systems modulated with 16QAM and 8QAM, the proposed 16ary and 8ary 3D-OFDM systems achieve signal-to-noise ratio (SNR) gains of 3 dB and 5 dB, respectively. Furthermore, the proposed 3D-OFDM system also exhibits an excellent performance in terms of peak-to-average power ratio (PAPR), with reductions of 0.3 dB and 0.4 dB, respectively. The proposed 3D-OFDM visible light communication (VLC) system is characterized with a better bit error performance.