Objectives <p>Self-compassion involves being kind to oneself during times of suffering and is linked to improved wellbeing. While there is a growing number of online self-compassion interventions, their effectiveness has not been well established. This systematic review sought to evaluate how well these online interventions enhance self-compassion and overall wellbeing.</p> Method <p>A search was conducted across PsycInfo, Scopus, Cinahl, Embase, and Education Research Complete for relevant publications using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. The search employed keywords according to the Population, Intervention, Comparison, Outcomes and Study (PICOS) criteria. Data on intervention types, program characteristics, populations, and outcomes related to self-compassion and wellbeing were extracted for synthesis.</p> Results <p>Twenty-one randomized controlled trials evaluating online self-compassion interventions with validated measures met the inclusion criteria, all conducted between 2014 and 2024. These studies were of moderately high quality. Most studies showed that the online interventions improved self-compassion, though their effects on wellbeing were inconsistent, with mixed results for hedonic wellbeing and delayed improvements in eudaimonic wellbeing. The review discusses findings related to different types of wellbeing, intervention formats, and program characteristics.</p> Conclusions <p>This systematic review assessed the effectiveness of online self-compassion interventions using only studies with randomised controlled trial (RCT) designs. It supports the efficacy of online self-compassion interventions, especially for enhancing blended wellbeing outcomes, which include both hedonic and eudaimonic aspects, aligning with contemporary views on optimal wellbeing. The review highlights the need for more rigorous studies with diverse populations and extended follow-ups to better understand the full impact of these interventions.</p> Preregistration <p>The review protocol was prospectively registered with PROSPERO (ID: CRD42021256775).</p>