Grass inflorescences produce the grain that feeds the world. Compared to eudicots such as Arabidopsis (Arabidopsis thaliana), grasses have a complex inflorescence morphology that can be explained by differences in the activity of axillary meristems. Advances in genomics, such as the completion of the rice (Oryza sativa) and sorghum (Sorghum bicolor) genomes and the recent release of a draft sequence of the maize (Zea mays) genome, have greatly facilitated research in grasses. Here, we review recent progress in the understanding of the genetic regulation of grass inflorescence development, with a focus on maize and rice. An exciting theme is the key role of plant growth hormones in inflorescence development.