This paper is set out to explore the students' attitudes towards online learning effectiveness using the Blackboard platform in three public Saudi universities (Taibah, Hail, and Al-Baha) during COVID- 19 pandemic. It examines the learning activities which ensure the achievement of education quality during unprecedented online learning. The survey based- questionnaire method was used to elicit students' responses. The numbers of students who participated in the survey are 333. The main section of the questionnaire contains questions about the main online learning activities. The coefficient relation of the p-value is highly correlated when tested using Pearson's r and Spearman's. The score of Cronbach's Alpha is (0.93) which indicates (greater internal consistency) an acceptable level of reliability. The findings positively emphasize the effective influence of online learning on student's academic achievements in most of learning factors except in an assessment factor where the development of new assessment methods is needed.