Here's What You Can Substitute For Oregano
Oregano is a relatively ubiquitous herb that is so frequently used because it works so well in such a wide variety of dishes. You can find it on pizza and in pasta, as well as in many poultry dishes. However, sometimes you may need to substitute, whether because of allergies or you simply ran out and haven't bought more.
Marjoram, like oregano, is a member of the mint family. It has a milder flavor than oregano, but many chefs will use both spices interchangeably. Marjoram can be used in place of oregano, but it won't hold up to longer cooking times, so it's important to add it at the end. You'll also want to use a little more — to substitute, use three parts of marjoram for every two parts of oregano (via Spiceography).
Another option is thyme, also a member of the mint family. Thyme works best in tomato-based recipes, as well as for beans, potatoes, meats, and vegetables — and it even works in salad dressing. It is a relatively adaptable replacement. Unlike marjoram, it can hold up to longer cooking times, making it ideal for Italian pasta sauces (via Raw Spice Bar). To substitute, use the same amount of thyme as oregano.
A substitute for oregano in vegetables and soups
Sage is another member of the mint family that will work as a substitute for oregano. It is best used in poultry dishes, but it also will work for vegetables and soups. To use as a substitute, fresh sage will be more effective. It can handle long cooking times and should be used in the same measurement as oregano.
A spice mix can also work. Italian seasoning already contains oregano so it can be a great substitute if you don't have oregano. Remember that it contains multiple spices, so keep track of what spices you're using and check the list of herbs and spices used in the Italian seasoning so as not to overdo any one spice.
By using any of these substitutes, you can finish recipes without oregano and still have them turn out as successful — and delicious — meals.