A search for the lepton flavor violating process Z → eμ is conducted with the ATLAS detector at the Large Hadron Collider in pp collisions using 140 ± 2.9 fb−1 of data collected at √s = 13 TeV in Run2. An enhancement in the eμ invariant mass spectrum is searched for at the Z boson mass. The number of Z bosons produced in the data sample is estimated using events of similar topology, Z → ee and μμ channels, significantly reducing the object reconstruction systematic uncertainty in the measurement. For the current blinding stage, an improved expected upper limit on the branching fraction Br(Z → eμ) < 1.52 × 10−7 at the 95% confidence level has been achieved.