This study investigated the effects of multimodal tasks on critical reading ability and perceptions of Thai university students. To compare effects on critical reading ability, students were randomly assigned to experimental and control groups and assessed with pre- and post-critical reading tests. Furthermore, reflective journals and semi-structured interviews were used to gain in-depth information about students' perceptions towards the multimodal tasks. The findings revealed that the experimental group with the treatment of multimodal tasks outperformed the control group in critical reading test scores. Furthermore, evidence from the reflective journals and semi-structured interviews showed that students generally had a positive perception of the multimodal tasks. The multimodal tasks not only assisted them in proposing critical reading ideas and fostered analytical thinking skills, but also enhanced intrinsic motivation and learning autonomy.