BackgroundIn a typical instructional setting, teachers are responsible for making ongoing decisions that involve judgments of students’ capabilities, knowledge, learning needs, and progress toward a certain pre-specified goal. However, there is a significant within-teacher as well as a great between-teacher variability in the actual determination of grades. Grades appear to be an amalgam of characteristics of a student, filtered through a range of teacher personality variables. AimsThe purpose of this study was to investigate the extent to which pre-service teachers agreed on students’ grades in writing task between holistic and analytic grading approaches and how their individual characteristics and beliefs about features of assessment explained the variability in grading practices. SampleTeacher candidates (N = 231, 65% female) enrolled in a training program in 2020 and 2021 cohorts at the University of València, Spain, were asked to read two essays, identified by experts as being of low and high quality, and assign holistic and analytic grades. Resultsalthough teacher candidates provided grades consistently across the two approaches (intra-individual differences), there was a high variability in the distribution among participants (inter-individual differences). We found that, gender, area of specialization, attitudes toward feedback, and extraversion were significant predictors of grading variability. ConclusionThis study highlights the considerable variation in grading practices among pre-service teachers, indicating the influence of individual factors such as gender, specialization, feedback receptivity, and extraversion. Despite consistent grading within specific approaches, the inter-individual differences in scores were substantial. Due to the consequential nature of teacher grades, our findings offer important insights and have critical implications for teacher preparation and professional development programs.