ICFP 2017 is the 22nd ACM SIGPLAN International Conference on Functional Programming. ICFP provides a forum for researchers and developers to hear about the latest work on the design, implementations, principles, and uses of functional programming. The conference covers the entire spectrum of work, from practice to theory, including its peripheries. ICFP will run in parallel to FSCD 2017, held at the Maths Institute in Oxford. Registrants of either conference can attend talks at both conferences, and the lunch/coffee breaks will be joint. (FSCD workshops will be held separately in the Department of Computer Science.)