Background Laparoscopy-assisted proximal gastrectomy (LAPG) with esophagogastrostomy using the double-flap technique has been reported to rarely cause gastroesophageal reflux. However, quantitative evaluation of the reflux has hardly been performed. The aim of this study was to clarify the superiority of the double-flap technique of LAPG with esophagogastrostomy compared with the OrVil technique in terms of preventing gastroesophageal reflux. Methods A total of 40 and 51 patients who underwent LAPG with esophagogastrostomy using the double-flap and OrVil techniques, respectively, for upper one-third gastric cancer were included in this study. Of these, 22 and 13 patients in the double-flap and OrVil groups, respectively, consented to undergo a 24-h impedance-pH monitoring test at 3 months postoperatively. Postoperative complications, including gastroesophageal reflux and anastomotic stricture, were assessed retrospectively. Results No significant differences were observed in the patients’ background between both groups, except for a higher D1+ dissection rate observed in double-flap group than in the OrVil group (93% vs 25%, P  < 0.001). Operative time was significantly longer in the double-flap group than in the OrVil group (353 min vs 280 min, P  < 0.001). All reflux % time was significantly lower in the double-flap group than in the OrVil group (1.29% vs 2.62%, P  = 0.043). On the other hand, the proportion of anastomotic stricture requiring endoscopic balloon dilatation was lower in the double-flap group than in the OrVil group but without statistical significance (18% vs 27%; P  = 0.32). Conclusions Despite its longer operative time and still relatively high anastomotic stricture rate, the double-flap technique would be better than the OrVil technique in terms of preventing gastroesophageal reflux in patients who underwent LAPG with esophagogastrostomy.