The aim of this article is to report the validity and reliability of Teacher Leadership Inventory (TLI). The sample of the study consists of 244 trained teachers who are chosen using random sampling technique from 19 secondary schools in Perak. The content validity, criterion validity and construct validity analyses have been carried out by using this set of data. The findings of this study using exploratory factor analysis through orthogonal rotation with varimax method has formed three factors, consisted of 15 items of TLI with factor loadings range from 0.54-0.84. The reliability Cronbach Alpha coefficient for the overall item is 0.85, meanwhile for each factors developed ranged from 0.66 to 0.91. As the conclusion, these analyses have generated a new pool of TLI item to measure the construct of Teacher Leadership elements in Malaysian Educational context. [For the complete proceedings, see ED600498.]