This study aimed to identify the effect of the effectiveness of the e-learning system, represented by its dimensions (system quality, information quality, service quality), on the academic performance of students in universities in the Sultanate of Oman under the Covid-19 pandemic. It also aimed to test the mediating role of teachers' capabilities and students’ motivation & capabilities for the proposed relationship. To achieve the goals of the study, the descriptive-analytical approach was used. The study population comprises all higher education students (127,962 students) in the Sultanate of Oman. Electronic questionnaires were distributed to the study population, and a convenient sample of (358) was collected. The data was analyzed using (SPSS). The findings showed a positive and statistically significant impact of the effectiveness of the e-learning system (system quality, information quality, service quality) on students' academic performance. The results showed that information quality is the most critical dimension of e-learning related to students' academic performance. The results also showed that teachers' capabilities and students' motivation & capabilities positively and indirectly affect the relationship between the effectiveness of the e-learning system and students' academic performance. The study reached several recommendations, the most important of which is for teachers and faculty members to receive courses on ways to use distance education through virtual programs and platforms. In addition, training students from the foundational stage to attend classes via virtual platforms and teaching them in distance education. And the need to study plans to establish an infrastructure with high capabilities to avoid network and maintenance problems and to seek studies in various fields in distance education and its development . Keywords: E-learning system effectiveness, Distance education, Corona pandemic, Student abilities, Student motivation, Teacher abilities, Student achievements.