This case study aims to empirically distinguish between common dimensions of inquiry-based instruction (IBI) and non-IBI dimensions. Furthermore, the authors were interested to identify the common and unique underlying dimensions of instruction that explain what kind of IBI is being provided within courses taught by instructors who describe themselves as making IBI part of their instruction. The findings reveal that IBI instructors' planning was more thorough and not directly tied to a textbook. IBI instructors scaffolded their courses through activities and evaluation of student learning.