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Subsurface drip irrigation (SDI) is a more efficient method of delivering water to the root zone compared to furrow irrigation, however, emitter spacing on the drip tape and depth of tape installation may influence irrigation efficiency. We evaluated the effects of emitter spacing (15, 20 and 30 cm) and drip tape depth (0, 15, and 30 cm) on yield and quality of drip-irrigated sweet onions (var. 1015Y) in two commercial field locations in South Texas. Yield and quality of drip- versus furrow irrigated onions were also compared. Approximately the same amount of irrigation water was applied to the different drip emitter and drip tape depth treatments (~ 549mm). About 21% more irrigation water was applied in furrow irrigated plots compared to SDI plots. Bulb yields ranged from 62.3 to 66.3 tons/ha for SDI and did not differ significantly among emitter spacing or depth treatments. Yields of SDI onions were however, greater than those of furrow-irrigated (~70% %) and dryland (271%) onions. Onion pungency (measured as pyruvic acid concentration) was higher in dryland (4.2%) and furrow-irrigated onions (3.8%) compared to SDI onions (3.2%).