In music, chromatic mediants, "are altered mediant and submediant chords." A chromatic mediant relationship is a relationship between two sections and/or chords whose roots are related by a major third or minor third, contain one common tone, or share the same quality, i.e. major or minor. For example, in the key of C major the diatonic mediant and submediant are E minor and A minor. Their parallel majors are E major and A major. The mediants of the parallel minor of C major (C minor) are E♭ major and A♭ major, and their parallel minors are E♭ minor and A♭ minor, totaling six chromatic mediants for that key. Thus an E major chord is one of six chromatic mediant chords in C major and the keys of C major and E major share a chromatic mediant relationship.

Chromatic mediants are usually in root position, may appear in either major or minor keys, usually provide color and interest while prolonging the tonic harmony, proceed from and to the tonic or less often the dominant, sometimes are preceded or followed by their own secondary dominants, or sometimes create a complete modulation.