Knowing which Gruyere cheese substitutes work best is a surefire way to stay on top of any recipe.
Gruyere Cheese Substitutes
There are numerous gruyere cheese substitutes, as there are various other cheeses with similar flavor profiles. Gruyere cheese is a popular hard Swiss cheese, made from cow’s milk, that is known for its nutty, salty flavor. The flavors of individual gruyere batches can vary as they age. Characteristically, gruyere has large holes throughout the cheese and may develop cracks when it is mature. It is an excellent melting cheese, which makes it popular for everything from fondue to sandwiches and pizza. 
Though it can be tempting, do not substitute cheddar for gruyere. Not only do they have different flavors, but they also melt very differently. If your local cheese counter doesn’t have gruyere, there are several other Swiss and French cheeses that can be substituted for it without affecting the recipe. Jarslberg, emmental, raclette, or comte work well.
Jarlsberg is a semi-soft cheese from Norway that comes with a yellow wax rind. Jarlsberg has a mild, almost sweet, nutty flavor, and large holes like gruyere. It is a preferred substitute for gruyere, due to the similar flavors and culinary versatility. It is also widely available at most cheese counters for a reasonable price.
Like gruyere, emmental is a very popular fondue cheese. A medium-hard Swiss cheese with large air holes, emmental is commonly used for bruschetta, tarts, and sandwiches. It has a pale yellow color, and a buttery, sharp taste.
Raclette is a semi-hard Swiss cheese that is traditionally served either melted or with hot beverages. It is popular for lasagnas and pasta because of its excellent melting powers. However, popular wisdom warns to not drink anything cold after eating a lot of raclettes. The cheese will harden in your stomach and cause indigestion. Therefore, this is a good substitute if you only need a small amount of cheese for a dish. 
An unpasteurized cow’s milk cheese from France, comte cheese is semi-hard and brine-washed. It is aged longer than gruyere, but still has a fresh taste and a creamy feel. Comte is also slightly sweeter than gruyere, but it melts fantastically and is particularly popular for cheese boards, fondues, and souffles. 
If you need a large amount of cheese, it might be more cost-effective to go for what is referred to as “American” swiss. This is the kind of swiss cheese commonly sold for sandwiches at grocery stores. You can also purchase it shredded. This kind of swiss cheese is younger, and therefore has more of a sour bite, but will adequately replace gruyere in any cheese-heavy recipe.