Category theory is a well-known mathematical modeling language with a wide area of applications in mathematics and computer science, including especially the semantical foundations of topics in software science and development. It is the intention of the ACCAT workshop to bring together leading researchers in the field of ACCAT with those in software science and development in order to transfer categorical concepts and theories in both directions. Thomas Soboll (University of Salzburg, Austria) Ulrike Golas (Konrad-Zuse-Zentrum für Informationstechnik Berlin, Germany) Dates: Sunday March 17th, 2013