This study investigated the effect of peer collaborative dialogue carried out in the text-based synchronous computer-mediated communication (SCMC) on the reading comprehension of EFL female students. Additionally, the study elicited EFL students' attitudes toward dyadic collaborative their discussions in SCMC during reading comprehension activities. The sample of the study comprised 36 Saudi EFL female students at Shaqra University. They were divided into two groups: an experimental group consisting of 18 students, forming nine pairs, to perform reading activities dialogically in Moodle and a control group of 18 students to perform reading activities individually in classrooms. The researcher used pre-post reading comprehension tests and a scale of SCMC-based dialogical collaborative reading attitudes. as research instruments to collect data. Data were analyzed using means and standard deviation, an independent sample t-test, a paired sample t-test, an Analysis of Variance test (ANOVA) and a one sample t-test. The findings revealed that there was a statistically significant improvement in the post-test average scores of the experimental group, which indicated the effectiveness of text-based dyadic collaborative dialogue on reading comprehension. Additionally, compared to other reading skills, making inferences skill was revealed to be the skill most affected by dyadic dialogues in SCMC. Besides, the participants exhibited positive attitudes toward their collaborative dialogues with peers in SCMC to foster their reading comprehension. Finally, pedagogical implementations and recommendations for future studies were suggested to explore the area of SCMC-based collaborative dialogue on language learning