We present a search for pair-produced vector-like top partners (``T quark'') using data from pp collisions at a center-of-mass energy of \sqrt{s}= 13~\mathrm{TeV} that were recorded with the CMS detector in the 2015 data-taking period. The search is carried out in the lepton+jets channel and is most sensitive for final states in which at least one T quark decays to a top quark and a Higgs boson. Since the final decay products tend to be collimated in the detector, jet-substructure techniques are used to identify boosted Higgs boson decays to . No deviation from the Standard Model (SM) background prediction is observed in the data and upper confidence level (CL) exclusion limits on the production cross section are calculated for multiple branching fraction scenarios of the T quark. Assuming a branching fraction of for the decay, T quark masses below 860 GeV (870 GeV expected) can be excluded.