To investigate the effect of functional electrical stimulation (FES) in improving activity and to investigate whether FES is more effective than training alone.Cochrane Central Register of Controlled Trials, Ovid Medline, EBSCO Cumulative Index to Nursing and Allied Health Literature, Ovid EMBASE, Physiotherapy Evidence Database (PEDro), and Occupational Therapy Systematic Evaluation of Effectiveness.Randomized and controlled trials up to June 22, 2014, were included following predetermined search and selection criteria.Data extraction occurred by 2 people independently using a predetermined data collection form. Methodologic quality was assessed by 2 reviewers using the PEDro methodologic rating scale. Meta-analysis was conducted separately for the 2 research objectives.Eighteen trials (19 comparisons) were eligible for inclusion in the review. FES had a moderate effect on activity (standardized mean difference [SMD], .40; 95% confidence interval [CI], .09-.72) compared with no or placebo intervention. FES had a moderate effect on activity (SMD, .56; 95% CI, .29-.92) compared with training alone. When subgroup analyses were performed, FES had a large effect on upper-limb activity (SMD, 0.69; 95% CI, 0.33-1.05) and a small effect on walking speed (mean difference, .08m/s; 95% CI, .02-.15) compared with control groups.FES appears to moderately improve activity compared with both no intervention and training alone. These findings suggest that FES should be used in stroke rehabilitation to improve the ability to perform activities.