Gilles de la Tourette syndrome (GTS) is a neuropsychiatric disorder of childhood onset, characterized by the presence of multiple motor and phonic tics. Early twin and family aggregation studies have suggested that genetic factors play a critical role in the development of GTS. However, identification of causative mutations and susceptibility regions has proved difficult. This may be attributed to various factors, including the clinical heterogeneity of GTS, the presence of comorbid psychopathology, gene-environment interactions and bilineal transmission. This review assesses the different methodologies of genetic studies with explanatory comment for the clinician, and summarizes key genetic findings in light of their potential implications for treatment strategies.