A large experimental campaign on the in-plane seismic response of rubble stone masonry walls is currently under development at the Structural Engineering platform laboratory at EPFL (Switzerland). The main objective of this campaign is the experimental investigation of the size effect on the in-plane seismic response of rubble stone masonry walls. Additionally, new experimental evidence is sought on strength and displacement capacities of rubble stone masonry and particularly on drift levels corresponding to axial load failure. A total number of fifteen walls are tested: four under simple compression, two under diagonal compression and nine under in-plane quasi-static cyclic shear-compression. Wallets of 900 mm × 900 mm are tested under simple and diagonal compression, and rectangular walls of three different sizes (side lengths of 700 mm; 1400 mm; 2100 mm) are tested under in-plane shear-compression loading. All walls have the same thickness (400 mm) and are constructed using the same material; irregular limestone units and lime-based mortar. Here, we present an overview of the experimental campaign, as well as the firs results on the simple compression and shear-compression tests.