Wheat plays a major role in organic agriculture around the globe. This chapter reviews the current state of organic cultivation of wheat and of its close relative, spelt, with a focus on crop diversification, through rotational design, use of species mixtures containing wheat, and diversification at the genetic level, e.g. through variety mixtures. The chapter shows that there are constraints associated with diversification in organic wheat cultivation systems. Diversifying rotations may dilute wheat production within the rotation; intercrops containing wheat are often characterised by unpredictability and technical difficulties; and diversification of wheat through evolving crop populations may be hampered by seed-borne diseases. The chapter concludes that optimisation of organic wheat cultivation systems across the world through diversification depends on a continuous and reliable, systematic and comprehensive collection of agronomic data under conditions of increased crop diversity.