Online education, as a type of distance education, has attracted the attentions of administrators, instructors, and students in recent decades. In the midst of the Covid-19 epidemic, online education has become an unavoidable need. Students' participation in such programs may have an impact on their learning and achievement. The current study looked at the link between engagement and achievement in online classrooms. As a result, the study used a correlational design to address the research questions using Dixon's Online Student Engagement Scale and a researcher-created achievement exam. The questionnaire was developed in 2015 and comprises four categories and 19 items on a seven-point Likert scale. In 2020, the questionnaire was modified with Google Form and distributed to 297 students enrolled in general English courses via a university LMS. The second instrument was a 40-item test of reading comprehension developed by the researcher. The examination was created on the basis of reading theories and was given as a final exam. The one-sample t-test findings indicated that students’ achievement and engagement levels are adequate. Quantile regression revealed a strong link between top achievers’ engagement and achievement. However, bivariate correlation revealed no statistically significant link between typical students’ engagement and achievement. However, students’ level of engagement perception was satisfactory. The concept of engagement applies to high achievers but not to ordinary or low performers, making measurement error possible.