This paper examines the characteristics of over-water gust factors and turbulence at three offshore locations, and evaluates several techniques for predicting over-water gusts. Mean gust factors were found to agree well with previously published values: typical average values for G(1,3600) and G(3,3600) at 13.4 m elevation were 1.34 and 1.30, respectively. Gust factors were found to be most sensitive to gust duration ( t), elevation ( z) and measuring interval ( T). Wave height, wind speed, and atmospheric stability were observed to have only slight influences on gust factors. Mean values for σ/u ∗ ranged from 2.26 to 2.58 in general agreement with published values. σ/u ∗ was observed to display less sensitivity to wind speed and elevation than σ/ U, suggesting it was a more stable parameter to use in modelling gust factors. The inclusion of stability effects in the calculation of u ∗ was found to decrease the height dependence of σ/u ∗ which was important for reliable gust factor prediction at higher elevations. The gust factor model evaluation revealed that a number of available models can provide good predictions of average gust factors. However, no model was able to account for the observed variation in individual over-water gust factors. Incorporation of the Geernaert et al. [(1987), Measurements of wind stress, heat flux and turbulence intensity turbulence storm conditions over the North Sea. J. geophys. Res. 92, 13127–13139] drag coeffecient/wave age relationship into an existing gust model did little to improve results. Several models were able to provide reasonable estimates of the peak gust occuring over a number of wind samples by adding a 95% confidence limit to the predicted maximum gust, or by increasing T to reflect the combined duration of all wind samples. A modified version of the Forristall [(1987) , Wind spectra and gust factors over water, Proceedings of the 20th Annual Offshore Technology Conference, Houston, Texas, 2–5 May 1988, OTC 5735, pp. 449–460] approach was recommended for use offshore where the vertical gust factor profile was important. Further work and better data are required to develop a modelling technique which can replicate the observed variability in over-water gusts.