  This volume contains the proceedings of the 12th International Symposium on
Games, Automata, Logic and Formal Verification (GandALF 2021). The aim of
GandALF 2021 symposium is to bring together researchers from academia and
industry which are actively working in the fields of Games, Automata, Logics,
and Formal Verification. The idea is to cover an ample spectrum of themes,
ranging from theory to applications, and stimulate cross-fertilization.
