While the pathways that produce plant pigments have been well studied for decades, the use by plants of nanoscale structures to produce colour effects has only recently begun to be studied. A variety of plants from across the plant kingdom have been shown to use different mechanism to generate structural colours in tissues as diverse as leaves, flowers and fruits. In this review we explore the cellular mechanisms by which these nanoscale structures are built and discuss the first insights that have been published into the genetic pathways underpinning these traits.