SimuPy is a framework for simulating interconnected dynamical system models and provides an open source, python-based tool that can be used in model- and system- based design and simulation workflows. Using SimuPy, it is easy to implement software representations of dynamical systems from numeric functions or from symbolic expressions using SymPy. SimuPy provides an API to connect these dynamical system models in block diagrams. The aggregate dynamics are automatically combined and can be simulated using the ordinary differential equation solvers provided by SciPy (or any solvers with the same interface). SimuPy can also handle event-based discontinuities by monitoring event functions, interrupting the integration upon a zero-crossing, and re-starting integration after using a root finder to determine the location of the discontinuity event.