Humeral shaft fractures account for 1% to 3% of all fractures. Traditional nonsurgical treatment with a functional brace is still the standard treatment of these fractures; however, modern studies have reported that nonunion rates may be as high as 33%. Recent information suggests that the development of nonunion after nonsurgical treatment may be identified as early as 6 to 8 weeks postinjury. Even with surgical treatment, nonunion rates as high as 10% have been reported. Regardless of the original treatment method, nonunion results in poor quality of life for the patient and therefore should be addressed. A thorough preoperative evaluation is important to identify any metabolic or infectious factors that may contribute to the nonunion. In most cases, surgical intervention should consist of compression plating with or without bone graft. Although most patients will achieve union with standard surgical intervention, some patients may require specialized techniques such as cortical struts or vascularized fibular grafts. Successful treatment of humeral shaft nonunion improves function, reduces disability, and improves the quality of life for patients. In this article, we outline our approach to the treatment of humeral shaft nonunion in a variety of clinical settings.