Objective: To investigate the effectiveness of aquatic exercise in the management of musculoskeletal conditions. Data Sources: A systematic review was conducted using Ovid MEDLINE, Cumulative Index to Nursing and Allied Health Literature, Embase, and The Cochrane Central Register of Controlled Trials from earliest record to May 2013. Study Selection: We searched for randomized controlled trials (RCTs) and quasi-RCTs evaluating aquatic exercise for adults with musculoskeletal conditions compared with no exercise or land-based exercise. Outcomes of interest were pain, physical function, and quality of life. The electronic search identified 1199 potential studies. Of these, 1136 studies were excluded based on title and abstract. A further 36 studies were excluded after full text review, and the remaining 26 studies were included in this review. Data Extraction: Two reviewers independently extracted demographic data and intervention characteristics from included trials. Outcome data, including mean scores and SDs, were also extracted. Data Synthesis: The Physiotherapy Evidence Database (PEDro) Scale identified 20 studies with high methodologic quality (PEDro score =6). Compared with no exercise, aquatic exercise achieved moderate improvements in pain (standardized mean difference [SMD]=-.37; 95 confidence interval [CI], -.56 to -.18), physical function (SMD=.32; 95 CI, .13-.51), and quality of life (SMD=.39; 95 CI, .06-.73). No significant differences were observed between the effects of aquatic and land-based exercise on pain (SMD=-.11; 95 CI, -.27 to .04), physical function (SMD=-.03; 95 CI, -.19 to .12), or quality of life (SMD=-.10; 95 CI, -.29 to .09). Conclusions: The evidence suggests that aquatic exercise has moderate beneficial effects on pain, physical function, and quality of life in adults with musculoskeletal conditions. These benefits appear comparable across conditions and with those achieved with land-based exercise.