Introduction: Ozone is a naturally occurring unstable compound with three oxygen atoms that generally transforms into an oxygen molecule, releasing one oxygen atom. This feature has been exploited in dentistry for numerous applications, including for periodontal diseases and peri-implantitis. Methods: This review was performed in relation to the PRISMA flow chart and was annotated in the PROSPERO register. PICO questions were used as research questions. The risk of bias in the non-randomized clinical trials was appraised using the ROBINS-I tool. Results: An electronic search found a total of 1073 records, in particular, 842 from MEDLINE/PubMed, 13 from Bio Med Central, 160 from Scopus, 1 from the Cochrane library databases, and 57 from the PROSPERO register. A total of 17 studies were included in the present systematic review. Information regarding the characteristics of the periodontal clinical and radiographic parameters for gaseous ozone, ozonate water, ozonate oil, and ozone gel, including clinical attachment loss (CAL) probing depth (PPD), bleeding on probing (BoP), plaque index (PI), gingival index (GI), and marginal bone levels (MBL), were obtained. Conclusions: The studies included in this systematic review show different results regarding the ozone in periodontal treatment in association with or without SRP.