A gusseted bag has front and rear walls interconnected by a pair of side gussets and a slider-operated zipper. The zipper comprises a pair of profiled closure members that are engaged and disengaged by operation of the slider. No part of the side gussets is captured between the profiled closure members when the latter are interlocked. In one embodiment, the zipper extends beyond the front and rear walls on both sides thereof. In a fully closed position of the slider, at least part of the slider extending beyond one side of the front and rear walls. A sufficient portion of the slider extends beyond one side of the front and rear walls so that the first and second profiled closure members are interlocked across the entire width of the front and rear walls.