Inclusion Criteria:  Age 13-18 years Presence of OCD, as indicated by score on the Children's Yale-Brown Obsessive-Compulsive Scale Patient and one parent speak English fluently (to ensure comprehension of study measures and instructions Right-handed If taking psychotropic medications, these have been stable for > 6 weeks and are expected to remain stable for the approximately 3-week study protocol If currently in psychotherapy, symptom improvement has plateaued (no improvement in the past 6 weeks and symptoms expected to remain stable for the approximately 3-week study protocol)  Exclusion Criteria:  • Medical conditions contraindicated for TMS or EEG, including history of intracranial pathology, increased intracranial pressure, epilepsy or seizures, traumatic brain injury, brain tumor, stroke, implanted medical devices, possible pregnancy (female of childbearing age not using effective contraception), or any other serious medical condition (note that medical history will be reviewed by a study physician prior to TMS administration)  Metal in the head, except mouth (e.g., cochlear implant, implanted brain stimulators, aneurysm clips) Active suicidality or psychosis Existing diagnosis of Bipolar disorder, Autism Spectrum Disorder, mental retardation, or cognitive disability Substance abuse or dependence Taking a stimulant medication (and unwilling to forgo on study visit days) Taking medication with the potential to lower seizure threshold (e.g., neuroleptics, antipsychotics) Patient is a ward of the state Family history of epilepsy History of syncope