A series of compression and shear tests were conducted at large scale on joint surfaces in granite and slate specimens, with special equipment being used to isolate the deformations of the joints from those of the rock material. The matrix of compliance components for a rock joint is discussed in relation to these standard tests and it is shown that one pair of compliance components can be determined from a compression test and a second pair from a shear test. For the compression tests, the test results indicate a pattern of decreasing compliance with load, an increase in compliance with initial aperture, and high levels of recoverability of deformation. In the shear tests, the curves for the relative displacements indicate there are three zones of different behavior, elastic, transition and sliding