This book constitutes the refereed post-conference proceedings of the 5th International Workshop on Accelerator Programming Using Directives, WACCPD 2018, held in Dallas, TX, USA, in November 2018.The 6 full papers presented have been carefully reviewed and selected from 12 submissions. The papers share knowledge and experiences to program emerging complex parallel computing systems. They are organized in the following three applications; using openMP; and program evaluation.