In the present study, the detailed evaluation of nanomechanical properties in terms of hardness and Youngs modulus of duplex and compositionally graded YSZ based thermal barrier coating (TBC) have been evaluated by nanoindentation technique. Duplex and compositionally graded TBCs have been fabricated by thermal spray deposition technique. As TBCs are commonly applied for high temperature protection, effect of isothermal treatment in air (at 900 °C and 1000 °C) on nanomechanical properties has also been evaluated. Finally, the mechanical properties have been correlated with characteristics of the coating. The hardness and Youngs modulus of the TBCs are found to increase with increased duration of thermal exposure. Modulus of resilience and resistance to plastic deformation of the duplex and compositionally graded TBC have also been evaluated at room temperature and with thermal exposure and discussed in detail.