This paper reviews the published literature on the characteristics of mono-static radar sea-clutter observed with high grazing angles (typically above about 10°). To date, most of the analysis and modelling of sea-clutter has been undertaken at low grazing angles with the main application being for surface and airborne maritime radars. The paper identifies some of the data sets that have been collected and the empirical models that have been developed from them for the normalised radar crosssection. The amplitude statistics and Doppler spectra of high grazing angle clutter are reviewed and the implications for radar design and target detection are discussed.