Introduction <p>Adult spinal deformity surgery is frequently performed to address degenerative conditions and scoliosis, but postoperative complications such as proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) are common. These conditions can lead to neurological deficits and compromised surgical outcomes. This systematic review and meta-analysis aimed to evaluate the prevalence of neurological deficits associated with PJK and PJF.</p> Methods <p>A systematic review and meta-analysis was conducted following PRISMA guidelines. A comprehensive search was performed across multiple databases, including PubMed, Web of Science, Cochrane, Embase, and Scopus, with no language restrictions. Studies that reported neurological deficits following PJK or PJF after adult spinal deformity surgery were included. Data extraction and quality assessment were performed by two independent authors using NIH quality assessment tools. Meta-analysis was conducted using random-effect models, and heterogeneity was evaluated using <i>I</i>².</p> Results <p>Thirteen eligible studies were identified involving 2846 patients. Of these, 777 patients developed PJK or PJF, with 61 patients experiencing neurological deficits. The pooled prevalence of neurological deficits was 6.2% for PJF (95% CI: 0.062–0.192; <i>p</i> &lt; 0.001) and 7.1% for PJK (95% CI: 0.027–0.115; <i>p</i> &lt; 0.001). Heterogeneity amongst the studies was high for PJF (<i>I</i>² = 70.25%) and low for PJK (<i>I</i>² = 14.47%).</p> Conclusion <p>This study highlights the incidence of neurological deficits following PJK and PJF in adult spinal deformity surgeries. Future research should focus on identifying the risk factors and utilising evidence-based strategies that can improve postoperative care and reduce complication rates.</p>