This book constitutes the workshop proceedings of the 18th International Conference on Algorithms and Architectures for Parallel Processing, ICA3PP 2018, held in Guangzhou, China, in November 2018. The 24 full papers presented were carefully selected and reviewed from numerous submissions to the two following workshops: - ICA3PP 2018 Workshop on Intelligent Algorithms for Large-scale Complex Optimization Problems - ICA3PP 2018 Workshop on Security and Privacy in Data Processing