The aim of this research is to evaluate the potential of kaolin clay collected from different local Lebanese sources (Bekaa and North Lebanon) for use as supplementary cementitious material. Studies conducted on soil profiles across Lebanon have shown that some soils are likely to contain high kaolin content, and subsequently we can acquire Metakaolin from local resources. In fact, the samples were collected from each local source and were subjected to thermal treatment in order to develop their pozzolanic properties. Several characterization tests were implemented on the treated samples such as XRF, TGA/DTGA, FTIR and wet sieving. Moreover, early and ultimate compressive strength tests were performed on cement paste whereas standard strength activity index tests were conducted on mortars. The characterization of the treated samples was performed according to ASTM C311 in order to classify and select the optimal source as the best cementitious product. The results show that the chemical and physical properties of the treated samples matches the standard requirements of ASTM C618, which elucidate that the treatment process achieved in promoting an end product having pozzolanic potential. It was found that selected samples were satisfactory for being pozzolanic material and hence they are suitable to be classified as natural pozzolan according to ASTM C618. As a matter of fact, these end products can be used as partial replacement of the ordinary Portland cement, which will have positive impacts on the environment such as reducing CO2 emissions and minimize energy consumptions resulting from the production of cement. Keywords: Kaolin Clay, Supplementary Cementitious Materials, Metakaolin, Sustainability