The increasing demand for housing in emerging countries has driven the construction of a significant number of buildings using thin reinforced concrete (RC) walls with a single layer of reinforcement. Studies in Latin America have found buildings using walls as thin as 80 mm and as height as 7 stories. The advantage of this structural system relies on its economy and its construction speed; however, different concerns emerge about the seismic performance of buildings using this system. These relate to the possible lack of ductility, the scarcity of information about their behavior during earthquakes, and the absence of design guidelines supported by experimental research. Contributing to these needs, researchers have conducted several studies, most of them focused on experimental campaigns to assess the seismic behavior of thin RC walls. Despite these efforts, there is still need of more information about buildings constructed with this structural system, particularly about their analytical modelling. This research investigated the effect that different modelling assumptions have on the seismic performance assessment of buildings with thin RC walls. A six-story building constructed in Bogotá, Colombia using 100 mm walls reinforced with welded-wire mesh (WWM), was modelled in OpenSees using the shear flexure interaction multiple line vertical element model, with different assumptions for damping and steel behavior. In terms of damping, two Rayleigh damping schemes were used, one considering the initial stiffness and other with the current stiffness. For steel modeling, the material properties obtained from experimental testing were used for two approaches, one that considered buckling and other where it was ignored. For further comparison, models with deformed bars instead of WWM were created. The seismic performance of the different models was evaluated through incremental dynamic analyses, using the FEMA P695 ground motion suite. From these analyses, the interstory drift ratios, steel and concrete strains were recorded, which served as input for the development of seismic fragility functions. The results show that modelling parameters exert and influence at the different seismic performance levels, particularly on the collapse fragility of the WWM building. At the MCE level, the collapse probability observed for the WWM model with bar buckling was 14.8% higher than the model without buckling. This percentage was 7.4% for the model with damping proportional to the current stiffness compared to the model that used the initial stiffness. All things considered, the findings suggest that the modelling parameters have an influence on the analytical response of thin RC wall buildings