A search for direct production of top squark pairs in events with jets and large transverse momentum imbalance is presented. The data were collected in proton-proton collisions at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 35.9 fb-1. Dedicated object reconstruction tools are developed to exploit the unique signal characteristics. No significant excess of events above the standard model expectation is observed. Exclusion limits are set in the context of simplified models of top squark pair production under various decay hypotheses.