Student performance data is increasingly used to monitor and evaluate teachers. This study examines whether the turnover intentions – if teachers would change schools given the chance – of teachers in socioeconomically disadvantaged classrooms are moderated by teacher appraisal practices based on student academic performance data at the school system-level. Three-level hierarchical modelling in 46 education systems is conducted based on the Teaching and Learning International Survey (TALIS) from 2018. Results show that the effect of classroom socioeconomic composition on teacher turnover intentions increases as a function of performance-based teacher appraisal. However, this is only true when the appraisal is conducted by external authorities, and not so when conducted by the school management team. The models are then re-run by school consequences of appraisal such as dismissal, financial bonuses, or sanctions, and then by teacher characteristics, including gender, experience, and teaching subject. Experienced teachers in socioeconomically disadvantaged classrooms are more likely to change schools in school systems with more performance data-based teacher appraisal. These results underscore the potential pitfalls of performance data-based accountability systems for students in socioeconomically disadvantaged educational settings.