We consider string theory on AdS 3 × (S 3 × S 3 × S 1 )/Z 2 , a background supporting N = (3, 3) spacetime supersymmetry. We propose that string theory on this background is dual to the symmetric product orbifold of S 0 /Z 2 where S 0 is a theory of four free fermions and one free boson. We show that the BPS spectra of the two sides of the duality match precisely. Furthermore, we compute the elliptic genus of the dual CFT and that of the supergravity limit of string theory and demonstrate that they match, hence providing non-trivial support for the holographic proposal.