Abstract: An offshore tower structure comprising a base structure for positioning on and fixing to the sea bed, a central column for containing services such as conductors and risers and extending, in use, from the base structure to above the water level for supporting a platform, at least three support legs each extending between an upper portion of the column and the base structure at points spaced from the column for providing support for the column, and a bracing structure comprising a framework lying intermediate the ends of the column in a plane perpendicular to the longitudinal axis of the column, the framework connecting each pair of adjacent legs and each leg directly or indirectly with the column, and bracing elements between the column and the legs or between adjacent legs extending from the plane of the framework to respective points at or adjacent the base of the structure.