A statistical model is developed to predict wave overtopping of extreme waves on a fixed deck. The probability density function for the volume of overtopping water is based on the truncated Weibull distribution with the assumption of a local sinusoidal wave profile. The sensitivity to the wave nonlinearity parameter and deck clearance is discussed. The statistical model is compared to laboratory data for the instantaneous free surface elevation measured in front of a fixed deck and the instantaneous free surface elevation and overtopping rate measured at the leading edge of the deck. The statistical theory compared well with the measured exceedance probability seaward of the deck. Conditional sampling of the crest heights seaward of the deck gave a normalized probability distribution similar to that of the maximum water level measured on the deck for each overtopping event. The model prediction of the exceedance probability of deck overtopping gave very good agreement for large overtopping values.