While the Standard Model describes all known phenomena in
accelerator-based experiments, it leaves many important questions
unanswered: what is the reason for the large asymmetry between the
abundance of matter and anti-matter? What is the nature of dark
matter? In this talk I describe attempts to detect signals for physics
beyond the Standard Model using precision experiments at low
energies. In particular, I discuss the role of lattice QCD for
controlling hadronic uncertainties in the muon g-2, electroweak
precision observables and the proton radius.