  This article introduces a weak Galerkin (WG) finite element method for
quad-curl problems in three dimensions. It is proved that the proposed WG
method is stable and accurate in an optimal order of error estimates for the
exact solution in discrete norms. In addition, an $L^2$ error estimate in an
optimal order except the lowest orders $k=1, 2$ is derived for the WG solution.
Some numerical experiments are conducted to verify the efficiency and accuracy
of our WG method and furthermore a superconvergence has been observed from the
numerical results.
