SimpleITK is a simplified programming interface to the algorithms and data structures of the Insight Toolkit (ITK). It supports bindings for multiple programming languages including C++, Python, R, Java, C#, Lua, Ruby and TCL. These bindings enable scientists to develop image analysis workflows in the programming language they are most familiar with. The toolkit supports more than 15 different image file formats, provides over 280 image analysis filters, and implements a unified interface to the ITK intensity-based registration framework.