This book constitutes the proceedings of the Third International Symposium on Unifying Theories of Programming (UTP 2010) held at East China Normal University,Shanghai,China,November15-16,2010inconjunctionwiththe12th International Conference on Formal Engineering Methods (ICFEM 2010). This symposium followed on the success of the ?rst one, held at Walworth Castle (Durham, UK) in 2006, and the second, held at Trinity College (Dublin, Ireland) in 2008. Based on the pioneering work of C.A.R. Hoare, He Jifeng, and others on unifying theories of programming, the aims of this symposium series are, as stated in UTP 2008, to continue to rea?rm the signi?cance of the ongoing UTP project, to encourage e?orts to advance it by providing a focus for the sharing of results by those already actively contributing, and to raise awareness of the bene?ts of such a unifying theoretical framework among the wider computer science and software engineering communities. TheprogramfortheUTP2010symposiumincludesoneinvitedtutorial,three invited talks, and 12 regular paper presentations. I would like to warmly thank ourinvitedspeakers,AnaCavalcanti,HeJifeng,Je?SandersandJimWoodcock, as well asall the authors,for their enthusiasticand engagedparticipation in this event.