This lecture covers the vulnerability of unreinforced masonry (URM) walls to out-of-plane (oop) failure, discussing factors such as wall position, support, and quality. It also explores the force-displacement response of oop loaded URM walls, including the use of tri-linear models and empirical equations. Additionally, the lecture delves into storey response spectra for URM buildings, highlighting the importance of considering amplification by the structure and the effects of inelastic deformations.