GTS patients showed widespread structural connectivity deficits. Lower connectivity values were found specifically in tracts connecting the supplementary motor areas (SMA) with basal ganglia (pre-SMA–putamen, SMA–putamen) and in frontal cortico-cortical circuits. There was an overall trend towards negative correlations between structural connectivity in these tracts and YGTSS scores. Structural connectivity of frontal brain networks involved in planning, controlling and executing actions is reduced in adult GTS patients which is associated with tic severity. These findings are in line with the concept of GTS as a neurodevelopmental disorder of brain immaturity.