Although several research programs have investigated the performance of structural elements made of lightweight concrete, there is a limited understanding of the behavior of lightweight shear walls under seismic conditions. In this paper is summarized an experimental study that comprised quasi-static cyclic tests and shake table tests of twenty walls, conducted to provide information on the effect of lightweight and low-strength concrete on seismic performance of thin lightly-reinforced shear walls. Test results indicate that shear strength, drift ratios and energy dissipated at different limit states of lightweight concrete walls were larger in comparison to walls made of normalweight concrete. Measured performance also indicate that the reduction factor proposed by ACI 318-11 and NTC-C does not capture adequately the influence of lightweight and low-strength concrete. Thus, shear strength of thin lightly-reinforced, lightweight concrete shear walls can be calculated without any modification factor. © 2015 Elsevier Ltd.