Icing sugar is granulated sugar ground into very fine powder and mixed with an anti-caking agent. That anti-caking agent typically is gluten-free but sometimes (very rarely) wheat starch might be used to keep the sugar from clumping. Generally, you shouldn't worry about icing sugar containing gluten but always check the package to stay safe. Wheat starch is used very rarely, so most likely you will be just fine eating something with icing sugar on it!
Some brands, however, state that their icing sugar is gluten-free which means that there will be no cross-contamination. Other brands might process their sugar in a place that also processes wheat which creates the potential for cross-contamination. If you are celiac it would be safer for you to get those brands of icing sugar that have a "gluten-free" sign on the package.
Icing Sugar vs. Powdered Sugar
Icing sugar and powdered sugar are the same thing, so the same rules apply to buying powdered sugar as well.
Why Icing Sugar Can Potentially Have Gluten
Icing sugar tends to clump in the package and to avoid that, companies add an anti-caking agent to keep icing sugar nice and airy. That anti-caking agent is generally some type of starch, cornstarch, tapioca, or potato starch but very rarely wheat starch might be used. So, to be absolutely sure there is no gluten in your icing sugar pack, read the label and see what type of anti-caking agent the company used.
Gluten-Free Brands of Icing Sugar
These brands of icing sugar are gluten-free but to be sure you can also check the manufacturer's website for details!
These are the brands of icing sugar you would most likely be able to get in the US either online or in local stores.
This brand of icing sugar uses tapioca starch as an anti-caking agent. On their website, it is stated that this sugar is gluten-free which means that there should not be any chance for cross-contamination which is perfectly suitable for people with celiac!
This brand also uses tapioca starch, so it is both gluten and corn free. It does say on the package that the product is gluten-free which means that there should not be any cross-contamination.
This brand uses corn flour along with sugar. It doesn't say on the package that it is gluten-free but you could check with the manufacturer to see if it might have cross-contamination possibility.
This brand of icing sugar also uses tapioca starch as the anti-caking agent which makes this type of sugar both gluten and corn free! I am not sure if it states on the package that it is gluten-free but you can check if you come across this brand in a store!
This brand of icing sugar uses cornstarch as the anti-caking agent. Check the package to see if it is gluten-free or not or check the manufacturer's website for more info!
If you live in the UK you might be able to find these brands of icing sugar.
This brand uses tricalcium phosphate as the anti-caking agent and the brand stated on their site that all their products are gluten-free which is perfect for people with celiac!
This brand is also gluten-free and it uses cornstarch as the agent against clumping.
Tate and Lyle icing sugar is also gluten-free as stated on their website. The brand uses cornstarch to prevent clumping.
Asda also uses calcium phosphates to prevent clumping. This brand is also gluten-free and should be safe for people with celiac!
Recipes Using Icing Sugar
One of my favorite dessert recipes is the macaron recipe! There are a few methods to make macarons, and I have a recipe for the Swiss macaron shells, Churro macarons recipe, and macarons with dulce de leche filling (French method.
You can make icing for cakes, cookies, cinnamon rolls, and plenty of other recipes! Here is a recipe for gluten-free sourdough cinnamon rolls with cream cheese frosting that uses icing sugar.