A positioning mechanism for a vending machine is provided to properly align product containers for vending purposes. The vending machine includes a cabinet that establishes a product storage zone, a product delivery zone and a dispensing chamber. Arranged within the product storage zone are a plurality of shelves which include dividers that separate the shelves into a plurality of product queues. Each product queue includes an dispensing mechanism that releases a selected product from the product queue for delivery to the dispensing chamber. In addition, each product queue includes a positioning mechanism to align products in the product queue. The positioning mechanism includes a support member secured to the divider and a spacer bar pivotally secured to the support member. The spacer bar automatically adjusts to a width of a product container placed in the product queue in order to assure proper alignment of the product for dispensing.