Laparoscopic sleeve gastrectomy (LSG) is one of the most commonly performed procedures for the treatment of obesity. Patients with obesity are more prone to experience opioid-related adverse events (ORAE). The objective of this study is to determine if a multimodal analgesia protocol (MAP) reduces ORAE and provides effective pain relief for patients after LSG. This study was conducted at University Hospital, Singapore. The MAP consists of mandatory pre-operative etoricoxib, intra-operative acetaminophen, and post-operative acetaminophen with optional post-operative tramadol. We identified and collected data for patients who underwent LSG between May 2010 and November 2015 and compared patients before and after the implementation of the MAP. One hundred fifty-eight patients were included and 68 patients were treated with the MAP. There were no differences in age, gender, body mass index, ethnicity, or comorbidities between the two groups except for the incidence of hypertension (p = 0.015). There was a significant reduction in the incidence of ORAE from 33.3 to 8.8% (p