Peri-implant mucositis and peri-implantitis are increasingly prevalent, necessitating evidence-based maintenance strategies. Supportive peri-implant therapy (SPiT) protocols are proposed to limit disease progression and enhance clinical outcomes, yet their effectiveness remains variably reported. The authors aimed to systematically evaluate the effectiveness of SPiT protocols in preventing or reducing the progression of peri-implant diseases, with a primary focus on radiographic bone loss, clinical parameters, and patient-reported outcomes.A comprehensive systematic search was conducted in MEDLINE, Embase, Cochrane Library, and Web of Science through April 30, 2025. Eligible studies included randomized controlled trials, cohort studies, and case-control studies assessing professionally delivered SPiT. Risk of bias was assessed using the Cochrane of risk of bias tool for randomized trials ROB 2.0 and the Newcastle-Ottawa Scale for observational studies. Due to considerable clinical and methodological heterogeneity, results were synthesized narratively.Twenty-five studies met inclusion criteria: 9 randomized controlled trials, 13 cohort studies, and 3 case-control studies. SPiT, particularly with individualized, risk-based recall intervals, consistently improved clinical outcomes, such as probing depth and bleeding on probing compared with standard or no maintenance. However, substantial variability existed regarding adjunctive therapies, patient compliance, and reporting of systemic comorbidities. High clinical and methodological heterogeneity among studies, inconsistent documentation of systemic conditions, and variability in adjunctive therapies limited definitive conclusions and generalizability.Individualized risk-based SPiT protocols substantially enhance clinical outcomes and implant longevity compared with standard fixed-interval maintenance or no supportive therapy. Future research should standardize reporting, better account for patient-specific risk factors, and clarify the long-term effectiveness of adjunctive therapies. Risk-based SPiT protocols should be integrated into routine implant maintenance to improve clinical outcomes and reduce disease progression. Clinicians are encouraged to tailor recall intervals and adjunctive measures on the basis of patient-specific risk factors, including history of periodontitis, smoking status, and systemic health. Adopting individualized SPiT protocols can enhance implant longevity and minimize complications.