We review lattice results related to pion, kaon, D - and B -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 factor f + ( 0 ) , arising in the semileptonic K → π transition at zero momentum transfer, as well as the decay constant ratio f K / f π and its consequences for the CKM matrix elements V u s and V u d . Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of S U ( 2 ) L × S U ( 2 ) R and S U ( 3 ) L × S U ( 3 ) R Chiral Perturbation Theory. We review the determination of the B K parameter of neutral kaon mixing as well as the additional four B parameters that arise in theories of physics beyond the Standard Model. The latter quantities are an addition compared to the previous review. For the heavy-quark sector, we provide results for m c and m b (also new compared to the previous review), as well as those for D - and B -meson-decay constants, form factors, and mixing parameters. These are the heavy-quark quantities most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. Finally, we review the status of lattice determinations of the strong coupling constant α s .