pyFBS is a Python package for Frequency Based Substructuring. The package implements an object-oriented approach for dynamic substructuring. Current state-of-the-art methodologies in frequency based substructuring are available in pyFBS. Each method can be used as a standalone or interchangeably with others. Also a 3D display is available so a user can simply place and orient associated input/outputs used with each method. Furthermore, basic and application examples are provided with the package together with real experimental and numerical data.