Higher derivative couplings of hypermultiplets to 6
D, N= (1 ,0) supergravity are obtained from dimensional reduction of 10D heterotic supergravity that includes order higher derivative corrections. Reduction on T4 is followed by a consistent truncation. In the resulting action the hyperscalar fields parametrize the coset SO(4 ,4) /(SO(4) SO(4)). While the SO(4 ,4) symmetry is ensured by Sens construction based on string field theory, its emergence at the field theory level is a nontrivial phenomenon. A number of field redefinitions in the hypermultiplet sector are required to remove several terms that break the SO(4) SO(4) down to its SO(4) diagonal subgroup in the action and the supersymmetry transformation rules. Working with the Lorentz Chern-Simons term modified 3-form field strength, where the spin connection has the 3-form field strength as torsion, is shown to simplify considerably the dimensional reduction.