Abstract | A probabilistic treatment to the problem of rocking and overturning of a simply-supported rigid block is presented in the context of Performance-Based Earthquake Engineering (PBEE). To this end, a twodimensional rectangular block resting at ground surface on a rough, horizontal, tensionless and cohesionless rigid base is considered, subjected to a suite of 44 horizontal earthquake excitations. The roughness of the interface is assumed to be sufficiently large so that sliding is prevented, while the flexibility of the block and aerodynamic effects are neglected. Rocking response curves are calculated for increasing ground motion intensity (or decreasing uplift strength) via Incremental Dynamic Analysis (IDA), and results are summarized in the form of 16%, 50% and 84% fractile IDA curves. The solution based on a geometrically linearized rocking equation is advantageous, as it limits the problem parameters to just three that is, uplift “yield” strength, pseudo natural frequency and coefficient of restitution (damping), as in the classical yielding oscillator. On the other hand, the slenderness angle of the block is not an essential independent variable, as it simply normalizes the response angle. Generalized overturning criteria are proposed covering a wide set of excitations and block parameters. By employing non-linear regression analysis, simple formulae are developed for both the median/mean and the dispersion of response to provide a complete probabilistic characterization of rocking response for use in PBEE.