The purpose of this study is to develop the Metacognition Scale (MS) which is designed for primary school students. The sample of the study consisted of 426 primary school students in Izmir, Turkey. In order to examine the construct validity of the MS, exploratory factor analysis and confirmatory factor analysis were performed. For the validity of the MI, corrected item-total correlations were used. The corrected item-total correlations ranged from .35 to .65. In addition, t-tests between items' means of upper 27% and lower 27% points were compared. For each factor and each item, the differences between mean scores of upper 27% and lover 27% groups are significant. Finally, Cronbach alpha correlation coefficients were used. The internal consistency of the MS is .96 for the entire scale. The MS has eight scales: declarative knowledge, procedural knowledge and conditional knowledge, planning, self-control, cognitive strategies, self assessment and self monitoring. According to these findings, the MS is appropriate for researchers or teachers whose aim is to measure his/her students' metacognitive awareness and metacognitive abilities.