Connections Between Lattice Gauge Theory and Chiral Perturbation Theory

In this talk, I address the comparison between results from lattice QCD computations and Chiral Perturbation Theory (ChPT). I briefly discuss how ChPT can be adapted to the much-used quenched approximation and what it tells us about the special role of the ${\eta }^{\mathrm{\prime }}$ in the quenched theory. I then review lattice results for some quantities (the pion mass, pion scattering lengths and the $K^{+}\to {\pi }^{+}{\pi }^0$ matrix element) and what quenched ChPT has to say about them.