We performed a systematic review to examine the efficacy and outcomes of Botulinum Toxin A (BoNT-A) as the primary intervention strategy for patients with detrusor external sphincter dyssynergia. Eleven studies were included in the analysis (n = 353; 16% female, 84% male). BoNT-A was effective in 60%-78% of patients for reducing postvoid residual, mean detrusor pressure, detrusor leak point pressure, and mean urethral pressure 1 month after injection. Most patients required reinjection after an average of 4-9 months. BoNT-A was not associated with any significant adverse events, and may improve quality of life, as well as urodynamic parameters for detrusor external sphincter dyssynergia.