Constraints on the Higgs boson self-coupling are set by combining the single Higgs boson analyses targeting the , , , and decay channels and the double Higgs boson analyses in the , and decay channels, using data collected at TeV with the ATLAS detector at the LHC. The data used in these analyses correspond to an integrated luminosity of up to 79.8 fb for single Higgs boson analyses and up to 36.1 fb for the double Higgs boson analyses. With the assumption that new physics affects only the Higgs boson self-coupling (), values outside the interval are excluded at 95% confidence level. Results with less stringent assumptions are also provided, introducing additional coupling modifiers for the Higgs boson interactions with the other Standard Model particles.