The results of a search for squarks and gluinos in final states with an isolated electron or muon, multiple jets and large missing transverse momentum using proton-proton collision data at a center-of-mass energy of s=13??TeV are presented. The data set used was recorded during 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider and corresponds to an integrated luminosity of 36.1??fb-1. No significant excess beyond the expected background is found. Exclusion limits at 95%?confidence level are set in a number of supersymmetric scenarios, reaching masses up to 2.1?TeV for gluino pair production and up to 1.25?TeV for squark pair