Objective To explore the changes in T helper lymphocytes and their subsets in children with tic disorders (TD) and their clinical signifcance.Methods Flow cytometry was used to measure the percentages of T helper lymphocytes and their subsets in the peripheral blood of children with TD and healthy children (controls).Results The percentage of T helper lymphocytes was signifcantly lower in the TD group than in the control group (P < 0.001). The abnormal rate of T helper lymphocytes in the TD group was signifcantly higher than that in the control group (68.7% vs 18.8%; P < 0.001). The percentage of T helper lymphocytes was negatively correlated with Yale Global Tic Severity Scale score (r=-0.3945, P < 0.001). As for the subsets of T helper lymphocytes, the TD group had a signifcantly higher percentage of Th1 cells and a signifcantly lower percentage of Th2 cells compared with the control group (P < 0.001).Conclusions The abnormality of T helper lymphocytes and the imbalance of their subsets may be associated with the pathogenesis of TD in children. The percentage of T helper lymphocytes can be used as an indicator for assessing the severity of TD.