The purpose of this study was to examine effective design elements for online courses in the science, technology, engineering, and mathematics (STEM) fields at a large four-year public university in southeastern United States. Our research questions addressed the influence of online design elements on students' perception of learning and learning satisfaction. An online survey was completed by 537 students from 15 online STEM courses in spring 2016. The survey results indicated that student perceptions of learning and satisfaction were correlated with their perceptions of the efficacy of specific design elements, such as integrated active learning activities, interactive engagement strategies, and robust assessment design. In particular, perception of assessment design efficacy was significantly correlated with students' self-perceived learning and learning satisfaction for students of all subpopulations. The findings inform instructors and instructional designers on how to design effective, inclusive, and engaging online STEM courses. Student survey responses were observed to support universal design for learning (UDL) and in light of this, online STEM instructors are also strongly encouraged to utilize UDL principles in course design, which benefit not only students with disabilities but all students.