Abstract: The anomalous magnetic moment of the muon, g-2, has been measured and calculated with
very high precision. It is one of few observables which persistently show a deviation between experiment
and Standard Model prediction. In this talk the current status of the theory prediction will be reviewed,
with emphasis on the hadronic contributions which are the main source of the theoretical uncertainties.
The developments on the experimental side and the recently emerged discrepancy for the electron will
also be briefly discussed.