The aim of the present study is to reveal the impact of the interactive environment and metacognitive support (MS) in online learning on academic achievement and transactional distance (TD). The study is designed as 2 × 2 factorial design, and both qualitative and quantitative research techniques are used. The study was carried out on 127 students, and this research design was implemented in an online learning environment and evaluated based on an achievement test, TD scale, and semistructured interviews. The results of the study revealed that synschronous environments had a significant impact in reducing TD perception. In asynschronous environments, on the other hand, providing students with MS was efficient in reducing TD. In terms of academic success, compared with synschronous environments, MS provided in asynschronous environments caused to a significant difference in achievement test scores of the students. Explanations about findings and implications for instructional design are discussed in Conclusion section.