The purpose of this systematic review was to determine whether nurse-delivered weight management interventions improve weight outcomes across the life span. We conducted a comprehensive search of the PubMed, CINAHL, and PsycINFO electronic databases. We graded the trials using an adapted Jadad approach for methodological quality. The search identified a total of 1,159 citations; 23 articles from 20 studies were eligible for this review. Sixty-five percent of the studies reported significant findings related to body mass index (BMI) or weight reduction. Studies that were particularly successful at helping participants reduce weight and/or BMI involved nurses engaged in health promotion activities, operating within multidisciplinary teams and/or providing consultations, physical activity education, and coaching over the phone. Of the studies that involved long-term follow-up assessments, three out of nine studies showed a significant loss in weight or BMI between the intervention and control groups at follow-up times ranging from 12 months to 2 years.