Present investigation is focused on the effect of thermal barrier coated piston on the performance and emission characteristics of diesel engine using diesel as a fuel. The piston crown top surface were fully coated with three different combinations of thermal barrier coatings (TBC) materials like 7% YSZ, 2% Gd2O3 + YSZ, 5% Gd2O3 + YSZ with thickness of 0.25 mm and in all combinations the bond coat NiCrAlY were used with a thickness of 0.05 mm which is deposited on the target surface using plasma spray technique. Experimental analysis is carried out under different loading conditions in a four-stroke single cylinder diesel engine with diesel as a fuel. Results of this study reveal that the brake thermal efficiency of the coated engine is increased by 12.1% with reduction of brake specific fuel consumption by up to 16.2% compared to baseline engine. Experimental results also revealed that in coated engine Hydro carbon (HC) and carbon monoxide (CO) emissions were reduced by 17.8% and 18.4% respectively and also a significant increment of Nitrogen oxide (NOx) emission by 14.87% compare to baseline engine. © 2019 Informa UK Limited, trading as Taylor & Francis Group.