Objectives: To evaluate clinical outcomes of supportive peri-implant therapy (SPIT) following surgical treatment of peri-implantitis. Materials and methods: Twenty-four partially dentate patients with 36 dental implants diagnosed with peri-implantitis were treated by an anti-infective surgical protocol followed by regular supportive therapy. SPIT included removal of supra- and submucosal biofilm at the treated implants using titanium or carbon fibre curettes, or ultrasonic devices. In addition, professional prophylaxis (calculus/biofilm removal) at other implants/teeth and oral hygiene reinforcement was provided. Clinical measurements and radiographs were obtained at 1, 3 and 5 years. A successful treatment outcome was defined as implant survival with the absence of peri-implant probing depths (PD) ≥ 5 mm with concomitant bleeding/suppuration and absence of progression of peri-implant bone loss. Results: Twelve months after treatment, there was 100% survival of the treated implants and 79% of patients (19 of 24) had a successful treatment outcome according to the defined success criteria. At 3 years, 75% of the patients (18 of 24) had a successful treatment outcome, two patients (8%) were lost to follow-up (LTF), while 8% lost an implant, and two patients had recurrence of peri-implantitis. Between 3 and 5 years, an additional two patients were LTF, and an additional two patients each lost one implant. Thus, at 5 years 63% of patients (15 of 24) had a successful treatment outcome. Complete resolution of peri-implantitis, defined as absence of bleeding at all sites, was achieved in 42% of implants (N = 15) at 5 years. Conclusion: Five years following regular supportive therapy, the peri-implant conditions established following peri-implantitis surgery were maintained in the majority of patients and implants. Some patients had recurrence of peri-implantitis and some lost implants over the 5-year period. © 2016 John Wiley & Sons A/S.