Introduction <p>Gastroesophageal reflux disease (GERD) is a frequent postoperative concern after bariatric surgery, particularly following laparoscopic sleeve gastrectomy (LSG). This study aimed to identify clinical factors associated with GERD in patients referred for ambulatory pH monitoring following bariatric surgery.</p> Methods <p>This was a retrospective cohort study of adults who underwent ambulatory pH monitoring for GERD evaluation after bariatric surgery. All patients had prior LSG or Roux-en-Y gastric bypass (RYGB). The primary outcome was abnormal acid exposure time (AET), defined as distal esophageal pH &lt; 4 for ≥ 6% of the study period. Severe GERD was defined as AET ≥ 10%. Clinical factors and post-operative esophageal testing were assessed as potential GERD predictors.</p> Results <p>Forty-five patients were included (median age 52 years; 82% female). Testing occurred a median of 3.7 years post-surgery, with mean BMI reduction of 10.9 ± 5.46 kg/m2. Twenty-seven patients (60.0%) underwent 48-hour wireless pH monitoring, and 18 (40.0%) had 24-hour impedance pH monitoring. Among LSG patients (<i>n</i> = 24), 54.2% had AET ≥6% versus 28.6% after RYGB (<i>n</i> = 21) (<i>p</i> = 0.083). Severe GERD (AET ≥10%) occurred in 55.6% of LSG patients compared to 18.8% of RYGB patients (<i>p</i> = 0.028). BMI, reflux symptoms, proton pump inhibitor use, and findings on endoscopy, esophagram, and esophageal manometry were not associated with abnormal AET</p> Conclusions <p>In this cohort of post-bariatric patients, LSG was associated with a higher prevalence of severe GERD compared to RYGB. Other demographic and clinical variables were not associated with abnormal acid exposure, highlighting surgical history as the primary determinant of postoperative GERD in this population.</p>