Is mayonnaise gluten-free?

Yes, in almost every case. Traditional mayonnaise is an emulsion of egg yolks, oil, and an acid — usually vinegar or lemon juice — and none of those core ingredients are gluten-containing.

Why the base recipe is safe

Mayonnaise doesn't need wheat, barley, or rye for its texture; the emulsion comes from egg yolk, not a grain-based thickener. The acid is almost always distilled vinegar or citrus, both of which are gluten-free regardless of the starting grain, for the same reason covered on this site's vinegar page. Malt vinegar in mayonnaise is uncommon in Western brands, though it shows up more often in some imported and specialty styles.

The one style that's a genuine exception

Japanese-style mayonnaise, most widely known by the brand name Kewpie, is made differently: it typically uses rice vinegar as its base, but versions produced outside the US and EU sometimes use malt vinegar instead, which is not gluten-free. If you're reaching for a Japanese-style mayo specifically, check where it was made and look for a certified gluten-free label rather than assuming it follows the same recipe as Western mayonnaise.

Smaller things worth knowing

• Cross-contact from shared jars. Dipping a knife that's touched bread back into an open jar of mayo is a common, easy-to-miss source of contamination — a squeeze bottle avoids the problem entirely.
• Flavored mayonnaise. Chipotle, garlic-herb, or mustard-blended mayo can introduce gluten through the added flavoring (dijon mustard, in particular, carries its own small set of considerations — see this site's mustard page). Plain mayonnaise is the safer default when in doubt.

Practical guidance

Plain mayonnaise from a major Western brand is safe to treat as a default yes. For Japanese-style mayo, or any heavily flavored or imported mayo, check the label specifically rather than extending the same assumption.

FAQ

Is Kewpie mayo gluten-free? The US and EU versions typically are, but versions made elsewhere may use malt vinegar. Check the label and country of origin.

Does flavored mayo need extra checking? Yes — flavored blends are more likely to carry an added ingredient worth checking than plain mayonnaise is.

Sources

• Beyond Celiac, "Is Mayonnaise Gluten-Free?"
• Medical News Today, "Is mayo gluten free: Ingredients and finding gluten free mayo"