Formal Methods for Components and Objects Bernhard Beckert, Feruccio Damiani, Frank de Boer, and Marcello Bonsangue (eds.) Large and complex software systems provide the necessary infrastructure in all industries today. In order to construct such large systems in a systematic manner, the focus in development methodologies has switched in the last two decades from functional issues to structural issues: both data and functions are encapsulated into software units which are integrated into large systems by means of various techniques supporting reusability and modifiability. This encapsulation principle is essential to both the object-oriented and the more recent component-based software engineering paradigms. Formal methods have been applied successfully to the verification of medium sized programs in protocol and hardware design. However, their application to the development of large systems requires more emphasis on specification, modeling and validation techniques supporting the concepts of reusability and modifiability, and their implementation in new extensions of existing programming languages like Java. The 10th Symposium on Formal Methods for Components and Objects (FMCO 2011) was held at the Natural Science Museum in Turin, Italy, from October 3 to 5, 2011. FMCO 2011 was realized as a concertation meeting of European projects focussing on formal methods for components and objects. This volume contains 20 revised papers submitted after the symposium by the speakers of each of the following European projects involved in the organization of the program: - The FP7-IP project ASCENS on autonomic service-component ensembles. The contact person is Martin Wirsing (LMU Munchen, Germany). - The FP7-IST coordination action EternalS on trustworthy eternal systems via evolving software, data and knowledge. The action coordinator is Alessandro Moschitti (University of Trento, Italy). The four FP7 FET projects participating in the EternalS action are LivingKnowledge, HATS, Connect, SecureChange. - The FP7-STREP project ParaPhrase on parallel patterns for adaptive heterogeneous multicore systems. The contact person is Kevin Hammond (University of St. Andrew, United Kingdom). - The FP7-IP project PRO3D on programming for future 3D architectures with many cores. The contact person is Christian Fabre (CEA, France). - The ESF Cost Action IC0701, a European scientific cooperation on formal verification of object-oriented software. The chair of the action is Bernhard Beckert (Karlsruhe Institute of Technology, Germany). - The ESF Cost Action IC0901 ``Rich-Model Toolkit'', a European scientific cooperation on an infrastructure for reliable computer systems. The chair of the action is Viktor Kuncak (EPFL, Switzerland).