Management of a wide variety of musculoskeletal conditions requires the use of a cast or splint. Splints are noncircumferential immobilizers that accommodate swelling. This quality makes splints ideal for the management of a variety of acute musculoskeletal conditions in which swelling is anticipated, such as acute fractures or sprains, or for initial stabilization of reduced, displaced, or unstable fractures before orthopedic intervention. Casts are circumferential immobilizers. Because of this, casts provide superior immobilization but are less forgiving, have higher complication rates, and are generally reserved for complex and/or definitive fracture management. To maximize benefits while minimizing complications, the use of casts and splints is generally limited to the short term. Excessive immobilization from continuous use of a cast or splint can lead to chronic pain, joint stiffness, muscle atrophy, or more severe complications (e.g., complex regional pain syndrome). All patients who are placed in a splint or cast require careful monitoring to ensure proper recovery. Selection of a specific cast or splint varies based on the area of the body being treated, and on the acuity and stability of the injury. Indications and accurate application techniques vary for each type of splint and cast commonly encountered in a primary care setting. This article highlights the different types of splints and casts that are used in various circumstances and how each is applied.