There is a continuous debate on the validity of learning styles in literature. Several models have been proposed for the learning styles, corresponding to the psychometric assessment instrument. Among these models, Felder-Silverman model is widely used by educators to identify the learning styles of the engineering students. The instrument that measures the learning styles is the index of learning style (ILS). This study focuses to identify the validity and reliability of the ILS instrument for middle school students (N=260). This includes internal consistency reliability and construct validity report of the ILS. As a result of the study, the reliability of the instrument was established, however, it was found that there were cross loadings in the 14-factor solution and the 4-factor solution. Thus, the instrument validity for secondary grade students was not established.