Searches for new phenomena 
in final states involving leptons and jets using the ATLAS detector

Many beyond the Standard Model signatures predict new particles that decay into final state containing both leptons and jets. This talk will present new search results for massive particles by the ATLAS experiment using the full Run 2 dataset. A particular focus is given to searches for leptoquarks (LQ), that offer an attractive potential explanation for the lepton flavour anomalies seen at flavour factories, and heavy neutrinos, such as the Type I or Type III seesaw mechanisms which can explain the light neutrino masses.