This paper reports the development of the Negative Group Work Experiences questionnaire (NGWE), an assessment tool for measuring negative experiences of group work. Study 1 involved two samples of undergraduate psychology students (second-year sample n = 425; first-year sample n = 443), who completed research modules incorporating substantial elements of assessed group work. Participants completed a 39-item inventory designed to measure their negative experiences of group work as part of their general module evaluation. Exploratory and confirmatory factor analysis of the second-year sample indicated four interpretable and reliable factors: lack of group commitment, group fractionation, task disorganisation, and storming. Confirmatory factor analysis of the first-year data set confirmed and cross-validated the factor structure of the second-year sample. Study 2 (n greater than 254) confirmed the criterion validity of the NGWE. The NGWE is proposed as a useful tool for evaluating group processes, especially in large group teaching which involves collaborative group work. (Contains 6 tables and 1 note.)