Sixty patients with rotator cuff tears undergoing open repair were randomized to receive either gabapentin 600 mg daily in two divided doses starting 3 days before surgery and continuing for 1 week postoperatively (n = 30) or placebo (n = 30). The primary outcome was postoperative pain intensity (NRS) over the first postoperative week. Secondary outcomes included opioid (morphine, oxycodone) consumption, sleep quality and duration, side effects, and patient satisfaction. Outcomes were assessed repeatedly during hospitalization and daily until postoperative day 7. Overall, the gabapentin group had significantly lower pain scores from the first 24 hours to day 4, reduced morphine use in the first 6 hours and oxycodone use over 1 week, longer and better-quality sleep until day 5, and higher satisfaction, without increased adverse effects. These findings suggest that a perioperative gabapentin regimen can meaningfully improve early postoperative pain control and patient experience after open rotator cuff repair while reducing opioid needs.