The latest results on production of Higgs boson pairs at 13 TeV by the ATLAS experiment are reported, including a combination of six different decay modes. Results include $b\bar{b}\tau^{+}\tau^{-}$, $b\bar{b}b\bar{b}$, $b\bar{b}\gamma\gamma$, $b\bar{b}W^{+}W^{-}$, $W^{+}W^{-}W^{+}W^{-}$, and $W^{+}W^{-}\gamma\gamma$ final states, and they are interpreted both in terms of sensitivity to the SM and as limits on $k_\lambda$, a scaling of the triple-Higgs interaction strength. The strongest constraints to date on the $VVHH$ coupling are shown. Future prospects of testing the Higgs self-couplings at the High Luminosity LHC (HL-LHC) will also be presented.