A stabilized end notched flexure (ENF) test has been proposed for experimental characterization of Mode II interlaminar crack growth. A special displacement gage has been developed for direct measurement of crack shear displacement (CSD) that is the relative shear slip between the upper and lower crack surfaces of the ENF specimen. The test has been carried out under a constant CSD rate, ensuring that the crack growth is always stable. An analytical compliance method has been applied successfully to the stabilized ENF test. Fracture toughness, GIIc, and crack length are calculated from the load versus CSD diagram by using the analytical relationship between crack length and CSD compliance. A computer aided testing (CAT) system has been developed for continuous measurement of the crack length and fracture toughness. Fracture behavior of a unidirectional carbon/epoxy laminate has been examined during crack propagation as well as at the crack initiation by applying the proposed protocol.