Yes, if it's labeled microwave-safe. Not all glass is treated the same, and the wrong kind can crack under microwave heat.
Glass feels like a safe, neutral microwave material, but the microwave-safe label exists precisely because that assumption doesn't always hold. Different types of glass are made and tempered differently, and that affects how well they handle rapid, uneven heating.
The real question isn't whether it's glass — it's what kind of glass, and whether it has anything on it that a microwave shouldn't touch.
Tempered borosilicate or soda-lime glass made for cooking (like most modern Pyrex-style bakeware) is designed to handle the uneven, rapid heating a microwave produces. Manufacturers test and label these pieces specifically, so checking the bottom of the bowl for a microwave-safe symbol — usually small wavy lines — is the fastest way to know for sure, faster than guessing from how the glass looks or feels.
Glass cracks in microwaves mostly from thermal shock — a sudden, uneven temperature change, like pulling a bowl straight from the freezer and microwaving it, or setting a hot bowl on a cold, wet counter right after. Let frozen glass containers come closer to room temperature before microwaving them, dry the counter first, and avoid adding cold liquid to a bowl that just came out hot.
If the bowl itself gets noticeably hotter than the food inside it, that's a sign it's absorbing microwave energy it shouldn't be — a genuinely microwave-safe container should stay cooler than the food, since the food is what's meant to absorb the energy. Small hairline cracks, cloudiness that develops over repeated use, or a bowl that feels hot within the first 30 seconds of heating are all reasons to retire it rather than risk it shattering. A quick test: microwave the empty bowl next to a cup of water for a minute — if the bowl is hotter than the water, don't use it for food again — that's a reliable sign it's absorbing energy meant for the food. Manufacturers of true microwave-safe glassware design the material to be essentially transparent to microwaves, letting the energy pass through to the food instead, which is the whole point of the design and testing process behind that label.
Most kitchen glass bowls sold for cooking are microwave-safe by design, but a quick check of the label saves you from a cracked bowl and a mess. When it's unmarked or decorative, use something else.
Look for a small wavy-line microwave symbol stamped on the bottom. If there's no marking and you don't know the brand, it's safer to use a different container or avoid the microwave.
Thermal shock is the most common cause — going from very cold to hot too fast, or vice versa. Uneven heating in older or lower-quality glass can also create stress points that crack.
Modern Pyrex-branded glass bakeware is generally microwave-safe, but older vintage pieces made with different glass formulations may not handle thermal shock as well, so check age and labeling.
No — metallic paint, gold, or silver trim can spark and damage both the bowl and the microwave. Move food to a plain microwave-safe container instead.