The genetics of schizophrenia spectrum disorders have come a long way since the early demonstration of a substantial genetic component by family, twin and adoption studies. After over a decade of intensive molecular genetic studies, initially by linkage scans and candidate gene association studies, and more recently genome-wide association studies, a picture is now emerging that susceptibility to schizophrenia spectrum disorders is determined by many genetic variants of different types, ranging from single nucleotide polymorphisms to copy number variants, including rare and de novo variants, of pleiotropic effects on multiple diagnoses and traits. Further large-scale genome-wide association studies, and the forthcoming availability of affordable whole-genome sequencing technology, will further characterise the genetic variants involved, which in turn will be translated to improved clinical practice.