This book constitutes the thoroughly refereed post-workshop proceedings and the doctoral symposium of the 12th International Conference on Web Engineering, ICWE 2012, held in Berlin, Germany, in July 2012. The volume contains four workshops and a doctoral consortium, each focusing on specific research issues that contribute to the main themes of the ICWE conference: MDWE 2012: Eighth International Workshop on Model-Driven and Agile Engineering for the Web,  ComposableWeb 2012: Fourth International Workshop on Lightweight Integration on the Web,  WeRE 2012: Third Workshop on the Web and Requirements Engineering,  QWE 2012: Third International Workshop on Quality in Web Engineering.
