Around the world, about 10% of people prefer using their left hand. Handedness exhibits a consistent but modest (~25%) genetic component as reported across independent studies. Advances in genomic technologies combined with very large samples have led to the identification of specific genes associated with handedness. Most of these genes have a clear role in neurodevelopment, and the results provide evidence for shared biology contributing to handedness, cerebral asymmetries, and psychiatric disorders. It has become clear that human handedness is highly polygenic, and no individual gene is expected to play a major role. This chapter illustrates the methodology used in genomic studies and the implications of the most recent findings.