To aid with seismic design and assessment, the force-displacement capacity of a structural wall is commonly determined by evaluating a total rotation capacity comprising elastic and plastic deformation components, utilising a moment-curvature section analysis approach. The plastic rotation capacity is dependent on the adopted equivalent plastic hinge length. Although numerous equations for determining the plastic hinge length of slender walls are documented in the literature, their precision remains uncertain. This research collected a database of slender reinforced concrete wall specimens that demonstrated flexural failure modes, in order to evaluate the accuracy of the moment curvature method. For this purpose, the observed drift capacity is compared with the drift capacity estimated using commonly referred to equations for the plastic hinge length of reinforced concrete walls and subsequently, a new plastic hinge length expression is proposed to improve accuracy and reduce variability in predictions. Moreover, the displacement capacities of slender walls calculated using the moment-curvature method are contrasted with results from a direct rotation approach. (based on EN1998-03, ASCE 41-17, and ACI 369-22). The moment-curvature method aligns more closely with the experimental data compared to the direct rotation method and offers additional insights into the seismic performance of slender walls.