Background: A programme of construct validity research is necessary to clarify previous research on self-regulation and to provide a stronger basis for future research. Aim: A multitrait-multimethod (MTMM) analysis was conducted to assess convergent and discriminant validity of three self-regulation measures: the Learning and Study Strategies Inventory (LASSI; Weinstein, 1987), the Motivated Strategies for Learning Questionnaire (MSLQ; Pintrich, Smith, Garcia, & McKeachie, 1993) and the Meta-cognitive Awareness Inventory (MAI; Schraw & Dennison, 1994). Method bias across all three inventories was also examined. Sample and method: Three hundred and eighteen undergraduate university students (255 female, 61 male, 2 did not specify) were recruited from various courses to participate in research on perceptions about studying and study methods. Participants spent 30-60 minutes completing all three inventories. Results: Evidence for convergent validity was found at the matrix level, but was attenuated when examined at the individual parameter level. Evidence for discriminant validity among traits was modest, and common method bias was evident across all three measures. Conclusions: Results revealed the three inventories yielded different results, which suggests that researchers should be selective in the inventory they use to assess self-regulated learning (SRL).