Aim: The management of type 2 diabetes patients poses challenges for non-diabetologists healthcare professionals and may result in potentially inappropriate prescriptions of antidiabetic drugs which can be limited using screening tools. The aim was to set up nominal groups of healthcare professionals from several disciplines and develop a list of explicit definition of potentially inappropriate prescriptions of antidiabetic drugs. Methods: In a qualitative, nominal-groups approach, expert diabetologists, general practitioners, and pharmacists in France developed explicit definitions of potentially inappropriate prescriptions of antidiabetic drugs in patients with type 2 diabetes. The study was overseen by a steering committee and complied with the Consolidated Criteria for Reporting Qualitative Research. Results: Three nominal groups comprised a total of 30 participants (14 pharmacists, 10 diabetologists, and 6 general practitioners) and generated 89 explicit definitions. These definitions were subsequently merged and validated by the steering committee and nominal group participants, resulting in 38 validated explicit definitions of potentially inappropriate prescriptions of antidiabetic drugs. The definitions encompassed four contexts: (i) the temporary discontinuation of a medication during acute illness (n=9; 24%), (ii) dose level adjustments (n=23; 60%), (iii) inappropriate treatment initiation (n=3; 8%), and (iv) the need for further monitoring in the management of type 2 diabetes (n=3; 8%). Conclusion: This qualitative study is the first to have produced a specific tool of explicit definitions of potentially inappropriate prescriptions of antidiabetic drugs. Although the new list provides valuable insights, it must be validated by expert consensus (e.g. in a Delphi survey) before implementation in practice