This book constitutes the refereed proceedings of the 11th International Conference on Practical Applications of Agents and Multi-Agent Systems, PAAMS 2013, held in Salamanca, Spain, in May 2013. The 14 revised full papers and 9 short papers presented together with 16 demonstrations were carefully reviewed and selected from 70 submissions. The papers report on the application and validation of agent-based models, methods, and technologies in a number of key application areas, including: agents for real world problems; crowd modeling and analysis; decision making and discovery; interaction with artificial agents; mobility, ubiquity and clouds; (multi-)agent design technology; and simulation and organization.