Aim To compare the adjunctive effects of lasers or antimicrobial photodynamic therapy (aPDT) to non‐surgical mechanical instrumentation alone in untreated periodontitis patients. Materials and Methods Two focused questions were addressed using the Population, Intervention, Comparison and Outcome criteria as follows: in patients with untreated periodontitis, (a) does laser application provide adjunctive effects on probing pocket depth (PPD) changes compared with non‐surgical instrumentation alone? and (b) does application of aPDT provide adjunctive effects on PPD changes compared with non‐surgical instrumentation alone? Both randomized controlled clinical trials (RCTs) and controlled clinical trials (CCTs) were included. Results of the meta‐analysis are expressed as weighted mean differences (WMD) and reported according to the PRISMA guidelines. Results Out of 1,202 records, 10 articles for adjunctive laser and 8 for adjunctive aPDT were included. With respect to PPD changes, 1 meta‐analysis including 2 articles (total n = 42; split‐mouth design) failed to identify a statistically significant difference (WMD = 0.35 mm; 95%CI: −0.04/0.73; p = .08) in favour of adjunctive aPDT (wavelength range 650–700 nm). In terms of adjunctive laser application, a high variability of clinical outcomes at 6 months was noted. Two articles included patient‐reported outcomes and 10 reported on the presence/absence of harms/adverse effects. Conclusions Available evidence on adjunctive therapy with lasers and aPDT is limited by (a) the low number of controlled studies and (b) the heterogeneity of study designs. Patient‐reported benefits remain to be demonstrated.