The Sixth ESSA Summer School in Social Simulation was held in Wageningen, The Netherlands on 21-25 September 2015. The programme consisted of lectures from experienced social simulation modellers, student group work and hands-on practice on NetLogo. The Faculty included Andreas Ernst (University of Kassel, Germany), Gary Polhill (James Hutton Institute, UK), Tatiana Filatova (University of Twente, NL) and Gert Jan Hofstede (Wageningen University, NL), among others.