This is a Phase 3, randomized, double-blind, multicenter, placebo-controlled, 3-arm study with a 4 week treatment period. This study will compare the efficacy of Dexlansoprazole MR (30 mg QD and 60 mg QD) with that of placebo when administered orally as a single daily dose in the morning, before breakfast. The study is designed to evaluate symptom relief in subjects with symptomatic nonerosive GERD. Approximately 900 subjects will be enrolled at approximately 200 United States (US) and potentially ex-US sites. The study consists of two periods: a screening period, which will last a minimum of 7 days and a maximum of 21 days, and a treatment period, which will last 4 weeks.