Methods and apparatus for increasing flow uniformity are provided herein. In some embodiments, a slit valve having increased flow uniformity may be provided, the slit valve may include a housing having an opening disposed therethrough, the opening configured to allow a substrate to pass therethrough; a gas inlet formed in the housing; an outer plenum disposed in the housing and coupled to the gas inlet; an inner plenum disposed in the housing and coupled to the outer plenum via a plurality of holes; and a plurality of gas outlets disposed in the housing and fluidly coupling the opening to the inner plenum.