  This volume contains the proceedings of SOS 2009, the Sixth Workshop on
Structural Operational Semantics held on the 31st of August 2009 in Bologna,
Italy as a affiliated workshop of CONCUR 2009, the 20th International
Conference on Concurrency Theory.
  Structural operational semantics (SOS) is a technique for defining
operational semantics for programming and specification languages. The workshop
is forum for researchers, students and practitioners interested in new
developments and directions for future investigations in the area of SOS. One
of the specific goals of the workshop is to provide a meeting point for the
concurrency and programming language communities. Another goal is the
dissemination of the theory and practice of SOS amongst postgraduate students
and young researchers worldwide.
