Example aspects of a stiffening system for a hanger assembly, a hanger assembly, and method of reinforcing a hanger assembly are disclosed. The stiffening system for a hanger assembly can comprise a stiffener rod; a brace member oriented parallel to the stiffener rod; a stiffening connector coupling the brace member to the stiffener rod, the stiffening connector defining a connector hook and a fastener hole, the connector hook defining a hook recess, a portion of the brace member received in the hook recess; and a connector fastener extending through the fastener hole, the connector fastener pressing the stiffener rod into a corner region defined between the brace member and the stiffening connector.