Despite the popularity of Agile software development, achieving consistent project success remains challenging. This systematic literature review identifies critical success factors (CSFs) in Agile projects by analyzing 53 primary studies. Employing thematic synthesis with content analysis, our analysis yielded 21 CSFs categorized into five themes: organizational, people, technical, process, and project. Team effectiveness and project management emerged as the most frequently cited CSFs, highlighting the importance of people and process factors. These interpreted themes and factors contributed to the development of a theoretical framework to identify how these factors contribute to project success. This study offers valuable insights for researchers and practitioners, guiding future research to validate these findings and test the proposed framework using quantitative methods.