Squat-reinforced concrete shear walls are used as a gravity and lateral load resisting system in structures such as buildings and nuclear power plants. Due to their low aspect ratio, they are prone to shear or sliding failure. A shear wall was subjected to a cyclic test at the new Multi-Axis Sub-Assemblage Testing (MAST) facility at ETH Zurich. The shear to span ratio was 0.51 and a vertical load of 5.61% of the axial capacity of the wall was applied. The wall had a sliding failure, with a peak load capacity of 2760 kN. Digital Image Correlations (DIC) results show how the shear crack developed until sliding started and, from this point on, the majority of the wall deformation originated in the wall-foundation interface. Sliding displacements consisted of more than 50% of the total displacements of the specimen in large-amplitude cycles