A muntin clip supports a muntin grid inside an insulating glazing unit. The clip includes a positioning arm that allows the clip to be positioned with respect to the spacer. In one embodiment, the clip has a flat base adapted to be positioned on the inwardly facing surface of the spacer. The positioning arm extends from one side of the plate with the muntin-engaging body extending from the other side of the plate. The arm has an outer end that projects beyond the outer edge of the plate. A method for using the clip includes the step of using one of the glass sheets to engage and position the positioning arm of the muntin clip. Stops may be provided to limit the insertion of the clip into the spacer.