Background: The Approaches to Teaching Inventory (ATI) was developed to explore the relationship between students' approaches to learning, and teachers' approaches to teaching, in the physical sciences in higher education. It is increasingly being used in other contexts. Aim: To analyse the factor structure of the ATI. Method: Confirmatory factor analysis. Sample: Inventory responses from over 1,000 university teachers, from 4 different countries and a wide range of disciplines, experience, and teaching level (year of students' study) were used as the sample. Results: Cronbach's alpha values of the 2-scale inventory were acceptable for scale reliability, but not for the 4-scale structure. A good fit to the intended 2-factor structure was obtained by confirmatory factor analysis. Both Information transmission/teacher-focused and conceptual change/student-focused scales had well identified intention and strategy subscales. Conclusion: The ATI has been developed as a relational indicator of 2 dimensions of approaches to teaching. It is not intended for use in gathering a full, rich self-report of teaching, or in non-relational contexts. However, it has now been used in a number of different contexts, including different subject areas and cultures. There is evidence in this paper that in those contexts its factor structure is, in the main, consistent with the original design. This analysis also suggests ways that the ATI could be improved.