Studies have suggested that altered inhibition and excitation contribute to the pathology of Tourette syndrome, especially in cortical-striatal-thalamo-cortical (CSTC) pathways. GABA and glutamate were measured at 7T in large cohorts of healthy children and children with TS in regions of the CSTC network. GABA and glutamate were increased in the striatum. Glutamate was increased in the premotor region and correlated with reduced motor inhibition. These data support involvement of habitual behavioral pathways in TS. Historically the dopaminergic system has been considered to have a dominant role in TS; however, accumulating evidence strongly suggests involvement of GABA and glutamate neurotransmitter systems.