The goal of the study is to reveal the effect of activity-based media education on students' critical media literacy levels. A case study with fifth grade students was used in the study. A total of 18 students from a public school were participants. The data was gathered by a rubric and semi-structured interviews. Findings revealed that students have media literacy ability. Based on the result of the study, it can be suggested that either an independent media literacy course or a media literacy education integrated into other courses should be provided from the first grade. Furthermore, because of the fact that media literacy is closely related to critical thinking, teaching methods and activities in which students can gain critical questioning and thinking skills should be preferred.