he standard model predicts lepton flavour conservation. However, as evidenced by neutrino oscillations, lepton flavour is violated in nature. Since the dynamic responsible for lepton flavour violation (LFV) is unknow, it can be manifested in other processes and the search for it could lead to the discovery of physics beyond the standard model.

We will present a search in the data collected by ATLAS in 2015-2018 for LFV in Z decays. In the search, we employ a data driven method utilizing the approximate symmetry between electron-muon symmetry of the standard model. The method, challenges addressed, as well as the expected sensitivity of the search to discover LFV decays will be discussed.