Chords in F Dorian

F Dorian is built from the notes F, G, Ab, Bb, C, D and Eb. Its scale carries 3 flats. Harmonising that scale in thirds gives seven chords — 3 majors, 3 minors and 1 diminished — starting on Fm as the i. The chord on the fifth degree is Cm rather than a major V, so F Dorian has no leading tone and resolves by step and color instead of by dominant pull — the sound that separates it from a plain F major.

Beyond those seven, F Dorian commonly borrows F (I), Am (iii), Bb (IV), C (V) and Dm (vi) from the parallel major — the mixture chords that give a progression somewhere unexpected to go.