We argue that a class of ``non-critical superstring'' vacua is holographically related to the (non-gravitational) theory obtained by studying string theory on a singular Calabi-Yau manifold in the decoupling limit g_s0. In two dimensions, adding fundamental strings at the singularity of the CY manifold leads to conformal field theories dual to a recently constructed class of AdS₃ vacua. In four dimensions, special cases of the construction correspond to the theory on an NS5-brane wrapped around a Riemann surface.