This volume constitutes the post-proceedings of the 18th International Workshop on Implementation and Applications of Functional Languages. Fifteen full papers are presented. Each one was submitted to two rounds of reviews to ensure accuracy, thoroughness, and readability. The papers address all current theoretical and methodological issues in functional and function-based languages.

This volume presents the revised lecture notes of selected talks given at the Third Central European Functional Programming School, CEFP 2009, held in May 2009 in Komarno, Slovakia. It was co-organized with the TFP 2009 conference. The summer school included a three days warm-up session organized in Budapest, Hungary also in May, 2009.
The 11 revised full papers presented were carefully reviewed and selected. The lectures cover a wide range of topics such as design patterns, semantics, types, and advanced programming in various functional programming languages.

This volume presents the revised lecture notes of selected talks given at the Fifth Central European Functional Programming School, CEFP 2013, held in July 2013 in Cluj-Napoca, Romania. The 14 revised full papers presented were carefully reviewed and selected. The lectures cover a wide range of distributed and multicore functional programming subjects. The last 5 papers are selected papers of the PhD Workshop organized for the participants of the summer school.