Recent growth and institutionalization in the field of mixed methods research has provided fertile ground for a wide range of thoughtful criticism of how this research approach has been developed and conceptualized by some members of the mixed methods community. This criticism reflects the increasing maturity of the field as well as the different theoretical perspectives and methodological practices of researchers in different disciplines. While debates addressing these criticisms are likely to lead to valuable insights, no empirical studies have been carried out to date that have investigated researchers' critical views on the development and conceptualization of mixed methods research. This study examines the criticisms of the mixed methods field raised by a cross-national sample of researchers in education, nursing, psychology, and sociology. We carried out a secondary analysis of semi-structured interviews with 42 researchers and identified 11 different criticisms, which we classified in four domains: essence of mixed methods, philosophy, procedures, and politics. The criticisms related to the procedures domain were equally distributed among the four disciplines, while those related to the essence, philosophy and politics domains were more common among sociologists. Based on our findings, we argue that the divergence of views on foundational issues in this field reflects researchers' affiliation to different communities of practice, each having its own principles, values, and interests. We suggest that a greater awareness of this divergence of perspectives could help researchers establish effective collaboration and anticipate potential challenges when working with researchers having different methodological approaches.