The Laplace/Poisson solver Relax3d has been used extensively in cyclotron central region design and other accelerator and beam physics applications. It is typically run in an interactive mode where the user types in commands and parameters to initiate and control the solution process and to view or output the results. This paper describes a graphical user interface (GUI) that eliminates most of this typing and makes for more efficient user interaction. The use of a unique package called Expect (an extension to Tcl/Tk) allows the interface to be implemented as an independent front-end process that communicates with the running Relax3d program, thus requiring minimal modifications to Relax3d itself. Since Expect can control multiple processes, and since ReIax3d results are often sent to some subsequent program for visualization, particle tracking, etc., there are interesting opportunities to integrate these post-processing tasks into the same GUI.