Bidirectional transformations (BX) are a means of maintaining consistency between multiple information sources: When one source is edited, the others may need updating to restore consistency. BX have applications in databases, user interface design, model-driven development, and many other domains. This volume represents the lecture notes from the Summer School on Bidirectional Transformations, held at Lady Margaret Hall in Oxford during July 25-29, 2016. The school was one of the final activities on the project "A Theory of Least Change for Bidirectional Transformations", running at the University of Oxford and the University of Edinburgh from 2013 to 2017 and funded by the UK Engineering and Physical Sciences Research Council (grant numbers EP/K020919/1 and EP/K020218/1). The summer school was aimed at graduate students and researchers in BX and related areas. It played host to lectures from five external experts in BX, book-ended by some additional lectures from the TLCBX project team on the results obtained during the project.