Injury to the ulnar collateral ligament (UCL) of the first metacarpophalangeal (MCP) joint is commonly seen after a fall on an abducted thumb or after repetitive radial-directed stress. It is associated with several terminologies including skier’s thumb, gamekeeper’s thumb, and Stener lesion. There is often pain, swelling, and ecchymosis over the MCP joint of the thumb, and valgus stress in extension and flexion will show some degree of laxity. Imaging should include radiographs, in addition to ultrasound or MRI if a complete tear is suspected. In cases of a complete tear, referral should be made to a surgeon. Incomplete tears can be managed conservatively with immobilization until pain-free passive range of motion is achieved.