In music, the submediant is the sixth degree of the scale. For example, in the C major scale (white keys on a piano), the submediant is the note A; and the submediant chord uses the notes A, C, and E. In music theory, the submediant chord is symbolized with the Roman numeral VI if major or vi if minor.

"Submediant" also refers to a relationship of musical keys. For example, relative to the key of C major, the key of A major is the submediant. Modulation (changes of key) to the submediant are relatively rare, compared with, say, modulation into the dominant, and give a feeling of relaxation. Susan McClary says that modulation to the lowered submediant (in C: Ab) represents a dream like state of escape.

In German theory derived from Hugo Riemann the submediant in major is considered the tonic parallel (US relative), Tp, and the minor the subdominant parallel, sP.