In this study, the adhesion strength of thermal barrier coatings 8YSZ (ZrO2+8 wt.% Y2O3) deposited onNiCrAlY bond coats by atmospheric plasma spraying is investigated experimentally. A modified four-pointbending specimen that can generate a single interface crack to facilitate the control of crack growth wasadopted for testing. The fracture surfaces were examined using a scanning electron microscope. Images showthat cracks are initiated along YSZ/NiCrAlY interfaces, then kink and grow uniformly within the YSZ layer.The load-displacement curves obtained indicate three distinct stages in crack initiation and stable crackgrowth. Based on a microstructural model, finite element analyses were performed to extract the bondingstrength of the thermal barrier coatings. The fracture toughness of the plasma-sprayed 8YSZ coatings, interms of critical strain energy release rate Gc, can be reliably obtained from an analytical solution or from anumerical simulation of the cracking process using compliance methods.