Currently, prediction of interface strength is typically done using the critical energy release rate. Interface strength, however, is heavily dependent on mode mixity. Accurately predicting delamination therefore requires a material model that includes the mode dependency of interface strength. A novel test setup is designed which allows mixed mode delamination testing. The setup is a stabilized version of the mixed mode bending test previously described by Reeder and Crews [5.6]. It allows for the measurement of stable crack growth over the full range of mode mixities, using a single specimen design. The crack length, necessary for calculation of the energy release rate, is obtained from an analytical model. Crack length and displacement data are used in a finite element model containing a crack tip to calculate the mode mixity.@en