This book constitutes the refereed proceedings of the 6th International Conference on Games and Learning Alliance, GALA 2017, held in Lisbon, Portugal, in December 2017.  The 16 revised regular papers presented together with 6 poster papers were carefully reviewed and selected from 45 submissions. The papers cover topics such as games in education and training; games for health and special children; augmented and virtual reality; methods and tools (for desing and development); and poster abstracts.