Abstract: A zipper applicator operatively attachable to and usable with a horizontal form, fill, seal and separate packaging machine of the type used to make reclosable containers from a folded web of flexible material such as, for example, plastic film. The applicator is vertically adjustable with respect to the horizontal movement of web and zipper through the machine and includes a zipper eyelet for guiding the zipper into the applicator, a web guide that engages the fold of the web material, and an applicator guide for positioning the zipper with respect to the folded web so that the zipper can be attached thereto by the application of heat and pressure from a sealer mounted on the packaging machine. The vertical adjustability permits the applicator to be used for making bags of different sizes depending upon the width of the web material being run.