Objectives To evaluate bleaching efficacy and oral health-related quality of life (ORHQoL) of three bleaching systems with similar hydrogen peroxide (HP) concentration for up to 6 months post-treatment. Materials and methods A randomized controlled trial was designed with three parallel groups: group A — in-office 6% HP paint-on varnish; group B — at-home 6% HP with adaptable tray; group C — at-home 16% carbamide peroxide with custom tray. At three different stages (baseline, after bleaching, and 6-month follow-up), ORHQoL was evaluated by the OHIP-14 questionnaire and tooth color of the upper canines and central incisors were measured by two shade guides and a spectrophotometer (measuring CIE L*a*b* with respective color/whiteness differences − Δ E 00 /ΔWI D ). Results were presented as mean and 95% confidence intervals and statistical tests were performed appropriately, considering a significance level of α  = 0.05. Results All groups presented significant color differences ( P  < 0.05) between all stages, with Δ E 00 /ΔWI D surpassing the perceptibility threshold in 98% cases, with group C’s results being significantly ( P  < 0.05) higher when compared to other groups, although with significantly ( P  < 0.05) higher values of color relapse. Significative ORHQoL improvements ( P  < 0.05) were detected after bleaching in a global analysis with no differences between techniques. Conclusions All techniques presented bleaching efficacy, color stability, and improvements in ORHQoL up to 6 months post-treatment. Clinical significance Clinicians may consider both at-home and in-office bleaching techniques with 6% HP to attain long-lasting satisfactory clinical results while producing positive changes in ORHQoL.