Abstract: An apparatus and method of measuring the stress and strain characteristics of adhesives under uniform shear conditions. An Iosipescu sample (10) is used, in which at the shear line, the sample is joined by the adhesive to be tested. Pure shear is applied to the sample at the bond line and the distortion of the adhesive bond is measured. The apparatus (20) is attached to the specimen (10) by clamp means (30). The apparatus (20) comprises a fork means (22) and means to transmit the displacement (21) of the two parts of specimen (10) to the fork means (22) and means to measure the displacement, for example strain gauges attached to a Wheatstone bridge circuit. The specimen (10) with apparatus (20) attached is placed into a tensile testing machine especially adapted to receive the sample and apply shear to the adhesive bond line.