Academic achievement among students has become a visible indicator of educational effectiveness, especially in online learning. In particular, the ability to assess English students' knowledge necessitates a solid understanding of foreign languages such as English (EFL). It has something to do with reading achievement. Several researchers had already investigated the factors influencing college students' reading achievement in an EFL atmosphere during an online learning. Nevertheless, the coefficient of similarity between some of these factors as well as EFL students' epistemic beliefs has yet to be determined. The investigation shows a theoretical framework of demonstrates a prediction of a causal relationship between EFL epistemic beliefs and reading achievement during online learning. The potential relationship between them is determined by taking into account the current signs as well as numerous theories discovered as a result of research into the possible relationship among causality. As a result of this process, the study provided a deeper understanding of how students' epistemic beliefs are formed and influence their reading performance, which will influence their decision to use various reading methods to comprehend reading materials when online learning. In a broader perspective, the findings of this study have implications for online reading instruction.