The adhesive strengths of a soft, ductile polyester paint and a stiff, brittle epoxy resin on metal substrates equibiaxially strained to different levels were investigated by pull-off testing. The stress state in the samples after straining was estimated from relaxation tests on unsupported films. It was found that the epoxy behaved elastically at low strains and plastically at higher strains, whereas the polyester responded plastically at all levels of imposed strain. The pull-off stress of the polyester decreased strongly with increasing strain, indicating the formation of defects at the interface. No influence of the elastic strain in the epoxy coating on the pull-off stress could be detected. In both the epoxy and the polyester the location of failure moved towards the interface with increasing strain. After the onset of interfacial failure, the increase in area fraction interfacial failure with strain was found to proceed similarly in both materials.