In displacement-based engineering, the maximum interstory drift ratio (MIDR) is one of the most influential parameters for evaluating the seismic performance of existing structural systems. MIDR is also a key parameter in force-based designs satisfying serviceability lit-nits for new structural systems. A set of predictive equations is derived for estimating MIDR on shear-wall systems with fundamental periods ranging from 0.5 to 1.25 s. The equations are derived from a recently compiled ground-motion dataset that consists of 532 accelerograms recorded from 131 strong-motion events in seismically active regions in Europe and neighboring countries. The moment magnitude (M-w) values in the database are within the limits of 5 <= M-w <= 7.6 with recording distances of up to 100 km. The proposed equations estimate the interstory drift ratio for different horizontal component definitions (geometric mean, maximum and random). The equations include focal mechanism and site class as explanatory variables. The quadratic magnitude dependence and magnitude-dependent geometric decay are included in the functional form of the predictive model. To verify the functional form, residual and error analyses and a p-value test were done.