Searches for leptoquarks and other exotic processes in multi-lepton final states constitute a new probe to access new physics in the Standard Model flavour sector. The latest results from the ATLAS Collaboration are presented, covering a wide range of topologies. The analyses are performed exploiting the $139~\mathrm{fb}^{−1}$ dataset, recorded at the LHC with a centre of mass energy of $\sqrt s = 13~\mathrm{TeV}$. No evidence of new physics is found, thus setting exclusion limits on the various models.