During the last two decades, thin concrete walls have been frequently used to brace mid- to high-rise buildings in some Latin American countries. This structural system differs significantly in terms of wall geometry and reinforcement layout from traditional cast-in-place reinforced concrete wall buildings. Limited experimental data on this wall system and the absence of post-earthquake field observations make it difficult to assess whether such walls behave similarly to the walls designed according to the current local design code. The paper presents and discusses the results of an experimental program comprising quasi-static cyclic tests of four slender, thin and lightly-reinforced concrete walls with different geometrical configurations, steel properties and reinforcement layouts, which correspond to a common construction practice in Colombia. The seismic response of the specimens was assessed in terms of crack propagation and failure modes, hysteretic and backbone curves, contribution of rocking, flexural, shear and sliding components to lateral drift, stiffness degradation, and energy dissipation capacity. The results suggest that the response of these reinforced concrete walls does not meet the performance specified in the Colombian regulation if they are designed to reach the maximum lateral drift allowed by the code. © 2018 Elsevier Ltd