We review lattice results related to pion, kaon,D- andB-meson physics with the aim of making them easily accessible to the particle-physics community. More specifically, we report on the determination of the light-quark masses, the form factorf+(0), arising in semileptonicK→πtransition at zero momentum transfer, as well as the decay-constant ratiofK/fπof decay constants and its consequences for the CKM matrix elementsVusandVud. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants ofSU(2)L×SU(2)RandSU(3)L×SU(3)RChiral Perturbation Theory and review the determination of theBKparameter of neutral kaon mixing. The inclusion of heavy-quark quantities significantly expands the FLAG scope with respect to the previous review. Therefore, we focus here onD- andB-meson decay constants, form factors, and mixing parameters, since these are most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. In addition we review the status of lattice determinations of the strong coupling constantαs.