According to different usage purposes, VLC systems can choose either BIM (baseband intensity modulation) or SCM (subcarrier modulation) to modulate the carrier signal. This chapter mainly introduces various modulation schemes commonly used in VLC systems in these two modulation techniques, and the different effect of various modulation schemes of BIM on BER (bit error rate), bandwidth requirement, and flicker generated by optical modulation is also discussed. Additionally, the VLC-specific CSK (color-shift keying) scheme is also introduced.