This book constitutes the refereed proceedings of the 12th InternationalConference on Verification, Model Checking, and Abstract Interpretation, VMCAI 2011, held in Austin, TX, USA, in January 2011, co-located withthe Symposium on Principles of Programming Languages, POPL 2011.The 24 revised full papers presented together with 4 invited talks werecarefully reviewed and selected from 71 initial submissions. The papersshowcases state-of-the-art research in areas such as verification, modelchecking, abstract interpretation and address any programming paradigm, including concurrent, constraint, functional, imperative, logic andobject-oriented programming. Further topics covered are static analysis, deductive methods, program certification, debugging techniques, abstractdomains, type systems, and optimization.