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 daily Dexlansoprazole MR (60 mg and 90 mg) 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 non-erosive GERD. Approximately 450 subjects will be enrolled at approximately 120 U.S. and potentially ex U.S. 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.