Glasslock is the answer for leak-proof glass lunch boxes.

Glasslock makes the only glass lunch boxes I’d trust with soup in a bag.

The reason is the lid. Most snap-lock containers use plastic clips that bend, warp, or crack after a few months of dishwasher cycles and then the seal goes. Glasslock uses stainless steel latches that stay tight, plus a real silicone gasket that keeps liquids in. The gasket is also replaceable, so when it eventually wears out in a couple years, you buy a five-dollar seal instead of a whole new container set.

Pyrex’s Snapware line is the main alternative, and it’s decent, but the plastic latches get loose over time and the lids start leaking. Prep Naturals is fine for salads and dry stuff, but I wouldn’t trust those lids with anything runny. Ello has good glassware but their lid locks are clunkier and harder to clean.

One honest caveat: “leak-proof” still requires you to close the lid right. You have to press each latch down evenly and make sure the gasket is seated properly. If you slam the lid shut, any container will leak.

Wash the lids by hand and Glasslock will outlast your lunchbox habit. A soggy laptop bag is not where you save a few bucks.