This study investigates performance of clay based geopolymers at elevated temperatures and compares with the conventional geopolymer systems. Class F fly ash, calcined clay, metakaolin, and combination of fly ash-calcined clay are used as binders in various geopolymer mixes. The geopolymer specimens are exposed at 300, 600, and 900°C to evaluate the changes in physical, mechanical and microstructural characteristics which can be corroborated to their performance. Visual observations and mass loss variations showed that metakaolin specimens possessed the most intensive and branched cracking, even at 300°C exposure. Results of compressive strength test and thermogravimetric analysis (TGA) showed that fly ash and fly ash-calcined clay (FACC) mixes perform better than the other two mixes in long temperature range, especially when temperatures cross 120°C. Also, broader humps in the X-ray diffractograms of the FACC samples indicates a high degree of geopolymerisation. Thus, the paper supports the usage of the largely available clays in India after calcination and advocates the suitability of calcined clay for producing geopolymers to be used at elevated temperatures.