The compressive behaviour of a 0 degrees-ply (AS4/PPS) inserted between two acrylic layers is studied experimentally, and results are compared with existing theoretical predictions. A transparent acrylic is chosen so that kink formation in the 0 degrees-ply may be directly observed. Experiments show that failure occurs by catastrophic formation of an in-plane kink band with a kink band angle beta of 20 degrees to the horizontal axis. Then, as the compression strain is further increased, several additional kink bands appear. The load corresponding to the formation of the first kink is in agreement with theoretical predictions. These experiments confirm that failure initiates by in-plane kinking, and shed light upon the behaviour of an internal 0 degrees-ply inside a multidirectional laminate, especially the propensity for in-plane kinking versus out-of-plane kinking.