This manuscript reviews particle shape, its development in fine-grained soils (particle size D<~10mm) and coarse-grained soils (D>~100mm), shape characterization, and the role of particle shape on fabric formation and macroscale soil properties. Shape-dependent microscale mechanisms are hypothesized to explain previously published studies as well as new soil behaviour data. Particle shape emerges as a significant parameter that needs to be properly characterized and documented.