This book constitutes the refereed proceedings of the 13th International Conference on Practical Applications of Agents and Multi-Agent Systems, PAAMS 2015, held in Salamanca, Spain, in June 2015. The 10 revised full papers and 9 short papers were carefully reviewed and selected from 48 submissions are presented together with 17 demonstrations. The articles report on the application and validation of agent-based models, methods and technologies in a number of key application areas, including: agents and the energy grid, agents and the traffic grid, affective computing and agent development, ambient and contextual agents, social simulation and social networks and other agent-based applications.