BACKGROUND : Colorectal polypectomy is operator dependent, with variable rates of complete resection. The currently available assessment tools do not provide specific competency-based evaluation of provider technique. We aimed to validate the Global Polypectomy Assessment Tool (GPAT), a novel competency assessment tool for colorectal polypectomy. METHODS : GPAT was derived from the ESGE Curriculum for Training in endoscopic mucosal resection in the colon. Members of the curriculum taskforce plus three invited trainees and three medical students (collectively: the assessors) anonymously assessed nine endoscopic-view only polypectomy videos. The primary end point was the correlation of the assessors' GPAT scores with a consensus-derived reference GPAT score per video. Secondary end points were the assessors' subjective impression versus their GPAT score and interobserver agreement among assessors' GPAT scores. RESULTS : 171 GPAT assessments by 19 assessors (consultant gastroenterologists [n = 10], trainee gastroenterologists [n = 4], consultant surgeons [n = 2], and medical students [n = 3]) were analyzed. Reference GPAT scores did not differ significantly from those of the assessors (73.1 % [95 %CI 64.6 %-81.6 %] vs. 69.3 % [95 %CI 64.9 %-81.2 %]