Students are encouraged to develop a set of scientific skills and disciplinary practices common across the STEM disciplines. These skills (scientific inquiry, quantitative skills, laboratory and computational skills, communication skills, teamwork/interpersonal skills, interdisciplinary competency) are highlighted as important in discipline-based guiding documents -- biology (Vision and Change in Undergraduate Biology Education: A Call to Action), chemistry (American Chemical Society Guidelines and Evaluation Procedures for Bachelor's Degree Programs), and mathematics (A Common Vision for Undergraduate Mathematical Sciences Programs in 2025) -- for undergraduate teaching of biology, chemistry, and mathematics, and for the professional success of STEM college graduates. To promote interdisciplinary teaching and learning of STEM, we present a comprehensive comparison of the different disciplines' competency statements for undergraduate education. This organization and comparison of commonalities in scientific skills and disciplinary practices can be used by faculty and departments to come together to break down traditional silos, help their students more easily apply learning from one STEM discipline to another, and to create institutional change.