  We prove a Goldberg-Sachs theorem in dimension three. To be precise, given a
three-dimensional Lorentzian manifold satisfying the topological massive
gravity equations, we provide necessary and sufficient conditions on the
tracefree Ricci tensor for the existence of a null line distribution whose
orthogonal complement is integrable and totally geodetic. This includes, in
particular, Kundt spacetimes that are solutions of the topological massive
gravity equations.
