Numerous herbal supplements are presently marketed as weight-loss aids, but the efficacy of most is not proven. One such supplement is the extract of Citrus aurantium (bitter orange). The objective of this systematic review is to critically evaluate the evidence of efficacy for C. aurantium and weight management. Electronic databases, conference proceedings and pertinent journals were searched for relevant RCTs. Bibliographies and our departmental files were searched also. No restrictions on date or language of publication, age of participants or duration of treatment were imposed. Two reviewers independently determined the eligibility of studies, extracted data and evaluated the methodological quality of included studies. Seven studies were identified, of which four met the inclusion criteria. All RCTs had major methodological flaws. Two RCTs reported a marginal to statistically significant reduction in body weight and body fat in participants treated with C. aurantium-containing supplements, when compared to placebo. One trial reported a statistically significant reduction in body fat only, while the other reported a statistically significant increase in body weight. Adverse events included anxiety, elevated heart rate and musculoskeletal complaints. The evidence of efficacy for C. aurantium and weight management is contradictory and methodologically weak. Until more rigorous RCTs emerge, C. aurantium cannot be recommended as a treatment for weight loss.