The increasing population of older adults is accompanied by various psychosocial problems, including loneliness, which can negatively affect quality of life, psychological well-being, and social participation. Group-based social interventions represent a non-pharmacological approach that has the potential to address these issues by enhancing social interaction and support. This study aims to analyze the effectiveness of group-based social interventions in reducing loneliness and improving social participation among older adults. This study employed a Systematic Literature Review (SLR) method by searching for relevant articles in PubMed, ScienceDirect, and Google Scholar. The articles analyzed were studies published between 2022 and 2026 that met the inclusion and exclusion criteria. A total of 10 selected articles were descriptively analyzed using narrative synthesis. The findings indicate that various group-based social interventions, including group activity therapy, psychosocial programs, artistic and creative activities, nature-based activities, and technology-based interventions, have the potential to reduce loneliness and improve social interaction among older adults. However, intervention effectiveness varied depending on participant characteristics, types of activities, intervention duration, and research methods. Furthermore, several studies focused more on improving social interaction than on directly measuring social participation. This review concludes that group-based social interventions have the potential to support the psychosocial well-being of older adults by strengthening interpersonal relationships and encouraging engagement in shared activities. These findings may serve as a consideration for nurses and healthcare professionals in developing structured, sustainable, and needs-based community gerontological nursing programs.