OBJECTIVE: To characterize the presence and degree of postconcussion lightheadedness in relation to postconcussion vertigo and dizziness, and to determine whether lightheadedness influences overall symptom duration. DESIGN: Prospective, cohort design. SETTING: Nationwide Children's Hospital, Sports Concussion Clinic. PARTICIPANTS: Five hundred ten patients (9-19 years of age) within 30 days of concussion injury. MAIN OUTCOME MEASURES: Patient ratings (scale 0-6) of multiple postconcussion symptoms including lightheadedness, vertigo, and dizziness, reported from the day of clinic evaluation and recalled from the day of concussion. RESULTS: Postconcussion lightheadedness occurred commonly relative to vertigo. Lightheadedness was recalled more than vertigo (70.8% vs 48.6%, P < 0.001) on concussion day and reported more than vertigo (47.1% vs 24.1%, P < 0.001) on the day of clinic evaluation. Principal component analysis demonstrated strong correlations among lightheadedness, vertigo, balance difficulties, difficulty concentrating, mental fogginess, and difficulty remembering, relative to other postconcussion symptoms. When present on the day of clinic evaluation, these highly correlated symptoms predicted prolonged concussion recovery [P = 0.028; Hazard Ratio (HR) = 1.2]. Female sex (P = 0.04; HR = 1.23), emotional symptoms recalled from the day of concussion (P = 0.007; HR = 1.23), and cephalalgic symptoms (P < 0.001; HR = 1.34) reported on the day of clinic evaluation also predicted prolonged concussion recovery. CONCLUSIONS: Not all postconcussion dizziness is vertigo. Postconcussion lightheadedness is common and, when present at the time of clinic evaluation, can influence concussion recovery. CLINICAL RELEVANCE: Distinguishing postconcussion lightheadedness from vertigo may help to inform clinical treatment and concussion research design. This study adds to the growing body of evidence that supports an association between concussion and autonomic dysfunction.