OBJECTIVES: To evaluate the impact of interventions aimed at improving data quality in resident documentation in the residential long-term care setting, and to explore the experiences related with the implementation strategies and key determinants influencing data quality. DESIGN: A systematic review. SETTING AND PARTICIPANTS: Residential long-term care. METHODS: PubMed and Embase were searched from inception to January 2025. This search was supplemented with screening study registries, references, prospective citation searching, and reviewing gray literature. Studies were selected and data were abstracted by 2 researchers. A narrative synthesis and random effects meta-analyses were performed. The GRADE level of evidence was determined. A thematic analysis was conducted for the qualitative data. RESULTS: A total of 30 studies were included. The introduction of electronic health records, educational strategies, incident reporting systems, and reminder strategies were associated with small to moderate improvements. The average effect across interventions was an improvement of 13% (95% CI, 7%-20%, I CONCLUSIONS AND IMPLICATIONS: Small to moderate improvements in data quality were observed, with a very low GRADE of evidence. Most findings were limited to the completeness of documentation, although aspects such as timeliness and accuracy remain understudied. It remains unclear what interventions are effective in ensuring solid data quality.