Orthopedic surgery or orthopedics (also spelled orthopaedic surgery and orthopaedics in British English) is the branch of surgery concerned with conditions involving the musculoskeletal system. Orthopedic surgeons use both surgical and nonsurgical means to treat musculoskeletal trauma, sports injuries, degenerative diseases, infections, tumors, and congenital disorders.

Nicholas Andry coined the word "orthopaedics" in French as orthopedie, derived from the Greek words orthos ("correct", "straight") and paideion ("child"), when he published Orthopedie (translated as Orthopaedia: or the Art of Correcting and Preventing Deformities in Children) in 1741. The correction of spinal and bony deformities became the cornerstone of orthopedic practice.

In the United States orthopedics is standard, although the majority of college, university and residency programs, and even the American Academy of Orthopaedic Surgeons, still use the spelling with the Latinate digraph ae. Elsewhere, usage is not uniform; in Canada, both spellings are acceptable; orthopaedics usually prevails in the rest of the Commonwealth, especially in Britain.