This thesis describes research investigating the effectiveness of an online learning environment in a Saudi tertiary setting. A review of the literature examined the rationale and benefits of online learning and critical issues contributing to the effectiveness and quality of online learning environments, pertaining to learning theories and pedagogies associated with online learning, online instructional design, online communication, online instructor and online students. The examination of students’ and instructors’ experiences and perceptions of online teaching and learning assisted in gaining insights into the overall effectiveness of an online learning model, identifying the pedagogies and instructional design currently associated with online delivery, and determining a number of critical components that would construct an effective online learning environment in Saudi tertiary settings. Students’ experiences and perceptions of their online learning were discovered through quantitative and qualitative methods. The quantitative data on students’ experiences were gathered by using an adapted version of the Web-based Learning Environment Instrument (WEBLEI). The qualitative data on students’ experiences were collected by open-ended discussion questions attached to the WEBLEI survey. Instructors’ perceptions and experiences of their online teaching were investigated through a quantitative survey using written open-ended discussion questions. The study synthesised results from both qualitative and quantitative data and gives insight into constructing an effective online learning environment within Saudi tertiary sectors.