If you mean the main Toolset Palette, where you select which toolset opens in the Toolbox, then no, you can't. The tools are meant to be in logical order, so you can work through them one at a time, from top to bottom, in the most efficient fashion.
If you mean the order of the individual tools of the toolset, within the Toolbox, then yes you can. Use the little triangles in the header for each tool, which point up and down, to move the tool brick up or down in the list. This quick tip video shows how it works:http://youtu.be/kcS7CZ4geL8