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.