This book constitutes the thoroughly refereed proceedings of the Second Int- national Symposium on Unifying Theories of Programming, UTP 2008, held at Trinity College, Dublin, Ireland, in September 2008. This symposium followed on the success of the ?rst held at Walworth Castle in 2006. Based on the pioneering work on unifying theories of programming of Tony Hoare, He Jifeng, and others, the aims of this symposium series are 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. There were two invited talks, one of which appears here in full, the other in abstractform.We wouldliketo warmlythank bothJifengHe andRalph-Johann Back for their enthusiastic and engaged participation in this event.