Abstract: Background: Table tennis (TT) is an increasingly investigated intervention for supporting cognitive, motor, and psychosocial functions in older adults with neurodegenerative diseases, including Alz-heimer’s disease (AD), Parkinson’s disease (PD), and dementia. However, evidence remains fragmented, and the effect sizes and reliability of TT-based programs remain unclear. Materials and Methods: Following PRISMA 2020 guidelines, a systematic search of four databases (PubMed, Scopus, Web of Science, SPORTDiscus) was conducted through March 2025. Ten studies met inclusion criteria, with five eligible for quantitative synthesis. Random-effects meta-analyses (DerSimonian–Laird) were performed on cognitive and motor outcomes. Risk of bias was assessed using the JBI checklist, and certainty of evidence was graded using the GRADE framework. Results: Meta-analysis revealed large effects for cognitive outcomes (MMSE: d = 1.44; MoCA: d = 1.31), motor function (UPDRS-III: d = 1.27), and dual-task gait (TUG: d = 0.93), with low-to-moderate heterogeneity (I² = 18–42%). Sensitivity analyses confirmed the robustness of pooled effects. GRADE evaluations indicated moderate certainty. No serious adverse events were reported. Conclusions: Table tennis appears to be a safe, feasible, and effective non-pharmacological intervention for enhancing cognitive and motor outcomes in individuals with AD, PD, and dementia. Further high-quality trials with standardized protocols and mechanistic endpoints are needed to confirm these findings and expand clinical applicability.