Introduction: Botulinum toxin A (BoNT-A) injections in the prostate gland have been used as a minimally invasive option for treating bladder outlet obstruction (BOO). However, the efficacy of transurethral BoNT-A injections for BOO is not well established in the literature. The aim of this study is to collect evidence on the efficacy of transurethral BoNT-A injections for the treatment of BOO. Materials and methods: This systematic review and meta-analyses was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. A systematic literature search was performed till December 2022. The study population consisted of adult patients diagnosed with BOO, who underwent transurethral injections of BoNT-A for the treatment of BOO. Evidence synthesis: Out of 883 records, we identified seven studies enrolling 232 participants, of which only one nonrandomized controlled trial was found. Four prospective studies and two retrospective studies. Three studies included patients with lower urinary tract symptoms (LUTS) and benign prostatic hyperplasia (BPH) and were included in the meta-analysis. Three studies included patients with urethral sphincter hyperactivity. One study included patients with primary bladder neck disease (PBND). All studies showed significant improvements from baseline in maximum urinary flow rate (Qmax), International Prostate Symptom Score (IPSS), and postvoid residual (PVR) at 3 and 6 months. The adverse events were mild in all studies. Hematuria, UTI, and urinary retention were reported across all studies. Conclusion: In conclusion, transurethral BoNT-A injections have been shown to improve LUTS, QoL, and urodynamic parameters of individuals with BOO at 3 and 6 months after injections, and no serious adverse effects have been reported. However, data on the long-term benefits of this treatment are scarce, and more prospective, randomized studies with larger samples examining various injection techniques, dosages, and extended follow-up of recurrent injections are needed.