This book constitutes the refereed conference proceedings of the 21st International Conference on the Applications of Evolutionary Computation, Evo Applications 2018, held in Parma, Italy, in April 2018, collocated with the Evo* 2018 events Euro GP, Evo COP, and Evo MUSART.The 59 revised full papers presented were carefully reviewed and selected from 84 submissions. Evo Applications 2018 combined research from 14 different domains: business analytics and finance (Evo BAFIN); computational biology (Evo BIO); communication networks and other parallel and distributed systems (Evo COMNET); complex systems (Evo COMPLEX); energy-related optimization (Evo ENERGY); games and multi-agent systems (Evo GAMES); image analysis, signal processing and pattern recognition (Evo IASP); realworld industrial and commercial environments (Evo INDUSTRY); knowledge incorporation in evolutionary computation (Evo KNOW); continuous parameter optimization (Evo NUM); parallel architectures and distributed infrastructures (Evo PAR); evolutionary robotics (Evo ROBOT); nature-inspired algorithms in software engineering and testing (Evo SET); and stochastic and dynamic environments (Evo STOC).