It appears that much of the warming predicted by climate models occurs during stable atmospheric conditions. Such conditions prevail during night over the continental land and ice regions, and may occur during the whole day in wintertime. It is realized that the current representations ('parameterizations') of the stable boundary layer in weather forecast and climate models are still rather poor. At the same time, regional and global models do show great sensitivity to the model formulation of turbulent mixing in stable conditions. In this presentation we will provide an overview of the current status of understanding and parameterization of the SBL. Results will be given of an intercomparison study organised within the GEWEX Atmospheric Boundary Layer study (GABLS) as chaired by the author.