In light of the critical need for businesses to cultivate enduring customer relationships, this study investigates the role of customer gratitude (CG). Research has demonstrated that gratitude plays a transformative role in interpersonal relationships. Despite significant research growth in CG in recent years, there is a notable lack of comprehensive reviews in this field. This study conducts a systematic review of the extensive literature on CG and introduces a unified framework that identifies potential avenues for future research. The thorough review encompasses 44 articles spanning the period from 2005 to 2023, offering an in-depth exploration of the CG concept. The study synthesizes diverse literature on CG, by employing theories, contexts, characteristics, and methodologies (TCCM) framework as outlined by Paul and Rosado-Serrano (2019). The framework-based approach effectively provides a comprehensive analysis of the evolutionary trajectory of CG research over time. Findings of the study indicate that research on CG has been conducted in 16 countries, with a significant focus on the United States, where it has been featured in 19 studies. The majority of research in this area employed survey-based designs, followed by experimental and mixed-method approaches. Among the 25 theories used in CG studies, Social Exchange Theory is the most frequently employed. Based on the synthesis, a conceptual framework is proposed, outlining the antecedents, mediators, and consequences of CG. Additionally, the TCCM framework is utilized to structure potential trajectories for future research. This study makes various forms of contributions, including incremental, revelatory, and consolidatory contributions. Furthermore, marketers can capitalize on the insights gathered from this study to cultivate a nuanced understanding of CG across diverse industries and countries. The current study presents a thorough analysis of CG that has rarely been explored in depth previously.