Transactional distance has been defined as barriers to students' engagement with learning in the online environment. This research updates Zhang's (2003) scale of transactional distance, which quantified the extent of the barriers, in light of the massive changes in today's web-based learning environment. The resulting revised scale of transactional distance (RSTD) is a parsimonious version with 12 elements (compared to 31 original) that measure the transactional distance between student and teacher, student and student, and student and content. The RSTD has excellent factorial validity and reliability, yields better fit statistics, and is easier and less time-consuming to apply. The transactional distance values are unique predictors of student satisfaction, which is correlated to learning and persistence (a major concern with massive open online courses). This information can form the basis for a systematic approach to improving the design of today's contemporary open, flexible, distance education courses and thus serve as a valuable tool for researchers and educators alike.