A search for the bb ¯ decay of the Standard Model Higgs boson produced through vector-boson fusion is presented. Three mutually exclusive channels are considered: two all-hadronic channels and a photon-associated channel. Results are reported from the analysis of up to 30.6 fb -1 of pp data at s v =13 TeV collected with the ATLAS detector at the LHC. The measured signal strength relative to the Standard Model prediction from the combined analysis is 2.5 +1.4 -1.3 for inclusive Higgs boson production and 3.0 +1.7 -1.6 for vector-boson fusion production only.