Background <p>The Grit-S test is an eight-item questionnaire that is used preoperatively to identify patients’ level of determination and ability to work towards long term goals. It has been previously found that a higher preoperative Grit-S score is associated with greater postoperative success in orthopedic surgery and neurosurgical populations, but not with weight loss success after laparoscopic sleeve gastrectomy. The purpose of this study is to examine if there is an association between Grit-S score and outcomes for patients undergoing either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy.</p> Methods <p>A retrospective analysis of patients who completed the Grit-S questionnaire prior to undergoing either RYGB or sleeve gastrectomy between June 2022 and August 2024 was completed. The relationship between preoperative Grit-S score and weight loss at one year, readmission rates, and improvement of comorbidities was analyzed. Successful weight loss was defined as 20% total body weight loss.</p> Results <p>A total of 165 patients met inclusion criteria (RYGB 82.4%, sleeve gastrectomy 17.6%). Successful weight loss was achieved by 80% of the cohort. There was no significant difference between the average Grit-S score for patients with unsuccessful weight loss with a median of 3.67 (IQR 3.42–4.17) compared to patients with successful weight loss with a median of 4 (IQR 3.58–4.33) at one year postoperatively (p = 0.11). In addition, no relationship was found between Grit-S score and readmission rates (p = 0.70). Grit-S scores did not predict who no longer needed medications for diabetes, hyperlipidemia, or hypertension postoperatively compared to those who did (p &lt; 0.05 for all comparisons).</p> Conclusions <p>The Grit-S test may not be an accurate predictor of postoperative weight loss success after bariatric surgery. However, more research is necessary. Future efforts should focus on studying Grit-S score alongside other aspects of the preoperative psychiatric clearance process.</p>