<p>This study investigated the rheological properties of thermoplastic elastomer (TPE) foams filled with thermally expandable microcapsules by dynamic oscillatory shear tests. While linear viscoelastic data of the foams showed simple elastic-dominant behavior, nonlinear viscoelastic parameters obtained from Fourier-transform rheology exhibited two-step developments resulting from cell interfacial contribution at lower strain amplitude and macroscopic structural changes at higher strain amplitude. Intriguingly, the displacement component of normal stress difference exhibited its sign change from positive to negative right before the second development of shear nonlinearity started. The sign change of normal stress difference is speculated to be due to compressibility feature of foam cells and unknown interaction between matrix and cells. The shear nonlinear properties were correlated with cell structural factors in a power law manner. Using power law relationships, all shear nonlinearities of the foams could be reconstructed into a single master curve as a function of strain units rescaled by cell structural factors, indicating the universality of nonlinear rheological properties of polymer foams produced using TEMs.</p> Graphical abstract <p></p>