Chords in G Mixolydian

G Mixolydian is built from the notes G, A, B, C, D, E and F. It uses no sharps or flats at all. Harmonising that scale in thirds gives seven chords — 3 majors, 3 minors and 1 diminished — starting on G as the I. The chord on the fifth degree is Dm rather than a major V, so G Mixolydian has no leading tone and resolves by step and colour instead of by dominant pull — the sound that separates it from a plain G minor.

Beyond those seven, G Mixolydian commonly borrows Gm (i), Adim (iiø), Bb (bIII), Cm (iv) and Eb (bVI) from the parallel minor — the mixture chords that give a progression somewhere unexpected to go.