  An overview of the analyses that led to the observation of the Higgs boson
production in association with a top quark pair ($t\bar t H$) with the ATLAS
experiment is given. Up to 80 fb$^{-1}$ of proton-proton collision data
recorded by the ATLAS experiment at a center-of-mass energy of $\sqrt{s} = 13$
TeV at the Large Hadron Collider (LHC) have been used to achieve this major
milestone.
