The purpose of the current study is to determine the number sense performances and metacognitive awareness of primary school fourth grade students and the status of metacognitive awareness in predicting number sense. To this end, the study employed the relational survey model, one of the quantitative research methods. In the study, it was revealed that the number sense performances of the primary school fourth grade students were at a medium level and did not vary depending on gender. In addition, it was determined that the students' metacognitive awareness was at a high level and that metacognitive awareness did not vary significantly depending on gender. It was found that there is a positive correlation between the number sense performances and metacognitive awareness of the primary school fourth grade students. The students' metacognitive awareness was found to predict their number sense performances at a low level.