Educational assessment is a complex area of teacher professionalism involving negotiation of purposes and practices within sociocultural contexts. Developing teachers' assessment literacy has thus become a priority across education systems. Additionally, student teachers' assessment approaches and confidence in their assessment competence may be influenced by their personality and the prevailing educational cultures. This cross-cultural study on student teachers in Canada and Germany examined the relationship between personality traits and assessment literacy. Regression analyses revealed that self-rated assessment literacy was supported by sense of self-efficacy, suggesting that experiences of success in teacher education are important in developing assessment literacy. While summative approaches to assessment were not associated with personality, formative approaches were particularly influenced by personal values such as empathy and composure. Overall, the findings were fairly stable across the two educational contexts. Implications for teacher education in the field of assessment include an emphasis on leveraging student teachers' values.