BIOEQS is a global analysis and simulations program for complex biomolecular interaction data developed in the 1990’s [1, 2]. Its continued usefulness derives from the fact that it is based on a numerical solver for complex coupled biological equilibria, rather than on closed-form analytical equations for the binding isotherms. It is therefore quite versatile, allowing easy testing of multiple binding models and analysis of systems too complex for closed form solutions. However, a major drawback to a generalized use of this program has been the lack of a graphical user interface (GUI) for setting up the binding models and experimental conditions, as well as visualizing the results. We present here a new GUI for BIOEQS that should be useful in both research and teaching applications.