As IS become integral to our lives, individuals with intellectual and developmental disabilities (IDD) who often lack digital capabilities face increased risks of exclusion in everyday life. Inclusive IS designs are therefore essential. Yet, developing effective, inclusive designs requires integrating the perspectives of individuals with IDD. Thus, interviews with them become integral to develop IS designs mutually. However, existing guidelines from IS research lack applicability for interviews with individuals with IDD (e.g., need for accessible language), while guidelines outside of IS research miss IS specific considerations (e.g., engaging in complex IS functionalities). We propose 13 guidelines for interviews with individuals with IDD in design-oriented IS research developed through a three-step research process: A structured literature search to gatherinitial guidelines, followed by two phases of application and evaluation involving 13 individuals with IDD. The interview guidelines facilitate meaningful engagement of individuals with IDD in interviews, thereby advancing inclusive IS design research.