When performing tile-based graphics processing, a first vertex shading operation to generate vertex shaded position data for vertices is performed, and the vertex shaded position data used to prepare primitive lists indicating which primitives should be rendered for respective rendering tiles. Then, when processing a tile, a second vertex shading operation is performed for vertices of primitives for the tile for which fragments have been generated by a rasteriser prior to rendering the graphics fragments, to generate vertex shaded non-position attribute data for the vertices, based on the results of early depth testing before the fragments are rendered.