This book constitutes the refereed proceedings of the 6th IFIP TC 6 International Workshop on Self-Organizing Systems, IWSOS 2012, held in Delft, The Netherlands, in March 2012. The 5 revised full papers and 5 short papers presented together with 2 invited papers were carefully selected from 25 full paper and 8 short paper submissions. The papers address the following key topics: design and analysis of self-organizing and self-managing systems; inspiring models of self-organization in nature and society; structure, characteristics and dynamics of self-organizing networks; techniques and tools...