Fifty-six patients undergoing elective wrist/hand bone surgery with ultrasound-guided single-shot supraclavicular brachial plexus block (SCBPB) were randomized to receive intravenous dexamethasone 0.11 mg/kg (n=28) or intravenous 0.9% saline (n=28). The primary outcome was the difference in pain scores before versus after block resolution (NRS 0–10). Secondary outcomes included incidence of rebound pain (NRS ≥7 after block resolution), pain at rest/on mobilization at 6, 12, and 24 hr, time to worst pain, cumulative opioid use (IV morphine equivalents), patient satisfaction and sleep quality, and block/opioid-related complications through 24 hr. Overall, the results showed dexamethasone significantly lowered the primary pain-difference score and reduced rebound pain incidence, opioid consumption, and early postoperative pain, while delaying both block resolution and time to worst pain. These findings suggest a single dose of IV dexamethasone meaningfully attenuates rebound pain after SCBPB for wrist/hand surgery without increasing short-term complications.