Abstract: An air flow stabilizer having a pleated baffle system for attenuating turbulence and correcting non-uniform velocity distribution of gaseous flow through a flow conduit. The stabilizer is constructed from a plurality of baffle segments connected together in an accordion-like configuration edge to edge and angularly to one another. Each baffle segment has apertures to facilitate flow-through of gaseous flow parallel to and laterally across the axis of the flow stream. The baffle segments are secured to the flow conduit with support combs at the upstream end and the downstream end of the pleated baffle and reinforced by lateral stabilizing supports to provide a rigid structure.