This book constitutes the proceedings of the 27th International Conference on Verification, Model Checking, and Abstract Interpretation, VMCAI 2026, which took place in Rennes, France, during January 12-13, 2026.The 18 full papers presented in the proceedings were carefully reviewed and selected from 54 submissions. They deal with formal verification model checking, abstract interpretation, fostering interaction, cross-fertilization, and advancement of hybrid methods that combine these and related approaches.