In this paper, the authors introduce a research instrument (Draw a STEM Learning Environment: D-STEM) and its accompanying rubric (the D-STEM Rubric), both of which were developed based upon relevant research studies. The authors describe their usefulness to school principals in commencing conversations with their school's STEM [Science, Technology, Engineering, and Mathematics] leadership team and teaching staff, after their completion of the D-STEM instrument. The authors also suggest that, by using the D-STEM instrument, principals can unearth understandings of STEM teaching and learning in their school and importantly, together with the D-STEM Rubric, help reveal the characteristics of effective STEM teaching.