Previous meetings in the COMPLAS series were held in Barcelona in 1987, 1989, 1992, 1995, 1997, 2000 2003, 2005, 2007, 2009, 2011 and 2013. The first twelve conferences in the series were technically and academically successful and these meetings have become established events in the field of computational plasticity. We intend to make of COMPLAS XIII a step forward in the history of the COMPLAS conferences. The ever increasing rate of development of new engineering materials required to meet advanced technological needs poses fresh challenges in the field of constitutive modelling. The complex behaviour of such materials demands a closer interaction between numerical analysts and material scientists in order to produce thermodynamically consistent models which provide a response, while keeping with fundamental micromechanical principles and experimental observations. This necessity for collaboration is further highlighted by the continuing remarkable developments in computer hardware which makes the numerical simulation of complex deformation responses increasingly possible. The objectives of COMPLAS XIII are to address both the theoretical bases for the solution of plasticity problems and the numerical algorithms necessary for efficient and robust computer implementation. COMPLAS XIII aims to act as a forum for practitioners in the field to discuss recent advances and identify future research directions. COMPLAS XIII is one of the Thematic Conferences of the European Community on Computational Methods in Applied Sciences (ECCOMAS). It is also an International Association for Computational Mechanics (IACM) Special Interest Conference.