This is a Phase 1b, open-label, multiple-dose study of the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of NBI-98854 in a total of 36 pediatric subjects with Tourette syndrome (TS). The study will be conducted in approximately 18 male and female children (6 to 11 years of age) and approximately 18 male and female adolescents (12 to 18 years of age). Both age groups will be divided equally into 3 dosing cohorts with 6 subjects each. Ascending doses will be evaluated as part of a staggered-cohort design. Study drug will be administered in each cohort for 14 consecutive days.