Example ventilation air mixers and example air conditioning systems including ventilation air mixers are provided. One example ventilation air mixer comprises a branch air duct having an inlet that is configured to be coupled to a takeoff port of a main air source duct. The branch air duct has multiple holes arranged about a wall of a mixing portion. The trim air mixer at least partially surrounds the branch air duct and forms a cavity extending from the inlet of the branch air duct to at least the mixing portion. The trim air mixer has a trim air source duct connection coupled at an angle about a midsection. The angle is substantially acute relate to a longitudinal axis of the branch air duct such that trim air entering into the trim air mixer via the trim air source duct connection is directed toward the inlet of the branch air duct.