Authentic Tom Kha Gai (Thai coconut chicken soup)

Published: May 6, 2022 · Modified: Aug 20, 2025 by Pailin Chongchitnant · This post may contain affiliate links

When someone asks, "I'm new to Thai food, what should I make first?" Tom kha gai is my answer. Tom yum maybe the most famous soup of Thailand, but its milder creamier sister, tom kha gai, is my go-to when I'm in the mood for something comforting. This Thai coconut chicken soup is infused with the classic Thai herbs: lemongrass, galangal, and makrut (kaffir) lime leaves. This recipe is easy, quick, and a must-try for Thai food lovers.

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What is Tom Kha Gai?

Tom kha gai ต้มข่าไก่, which is sometimes spelled tom ka gai or tom kha kai, is one of the most popular soups amongst Thai food lovers. Tom means to boil, kha means galangal, and gai means chicken. So it's a chicken soup whose main flavour comes from galangal, but another key component not mentioned in the soup is coconut milk.

Tom kha gai soup is available at nearly every Thai restaurant overseas, but because it's such an easy recipe, it's a dish that's perfect for simple weeknight home cooking. Though chicken is the original version, you can make tom kha using other proteins. Typically in Thailand, alternative proteins are fish or seafood, as they pair best with the flavour profile of tom kha soup.

Tom kha gai is a great dish to make for a party because it is gluten-free, not too spicy, has easy-to-love flavours, and it can be made vegan with modifications I provide later on in this article.

Ingredients and Notes

Here are all the ingredients for my tom kha gai recipe and important notes about them. For the amounts, see the full recipe card below. There aren't that many, but each one is critical to the flavour of the soup. Kha in the soup name refers to the galangal, so that's the the one ingredient that cannot be substituted.

If you want to learn more about some of the Thai ingredients listed below, simply click the link to watch my "101" videos on them!

Boneless skinless chicken thighs. Chicken breast is okay to use, but the methods need to be modified as per the notes in the recipe card.
Chicken broth or stock, unsalted, preferably homemade. Good quality of the stock will greatly improve the final product.
Coconut milk. I recommend using UHT pasteurized coconut milk that comes in paper cartons as they taste much better than canned. Aroy-D is my preferred brand but Chaokoh is also okay to use. Read more about coconut milk quality in my guide to coconut milk.
Lemongrass, bottom half only, smashed until broken and cut into 2-inch pieces. Fresh or frozen are both acceptable in this recipe. Dried is not ideal, but okay if that's all you have. Do not use powdered lemongrass.
Galangal, thinly sliced into rounds. This is a key flavour of the soup so it cannot be skipped or substituted. Some people say you can use ginger, and while you can use it, the flavour will not be the same. If fresh is not available, look for frozen galangal at your Asian grocery store. *If your frozen galangal comes in a whole piece, let it thaw at room temp for 10-15 minutes just until it's soft enough to slice. Put it back in the freezer after you've sliced off what you need. Do not let it thaw completely or it'll turn mushy.
Makrut lime leaves (aka kaffir lime leaves), twisted to bruise and torn into chunks. Fresh or frozen will work for this. Dried is not ideal, but okay to use if that's all you have.
Thai chilies, smashed just until broken. This soup is not meant to be very spicy, so letting whole, broken chilies gently infuse into the soup gives just enough of a kick. If making this soup for kids you can omit the chilies altogether.
Oyster mushrooms or another Asian mushroom. In Thailand straw mushrooms are traditional, but since they are not available here my preference is for oyster mushrooms.
Fish sauce.
Palm sugar. If not available you can sub light brown or white sugar. Since it is used in a small amount, what kind of sugar you use is not important.
Cilantro or green onions for garnish
Fresh lime juice

How to Make Tom Kha Gai

Here's a bird's eye view of how to make tom kha gai, but to ensure success, be sure to watch the video tutorial in the recipe card below as it's always good to see how it's done, and I often include extra tips you don't want to miss!

Bring chicken stock and salt to a boil, add the chicken and simmer for 15 minutes until fork tender.
Add coconut milk.
Add the herbs and the chilies.
Add the mushrooms.

Process shots for making tom kha gai steps 5-8

Add about half of the fish sauce and sugar and simmer for 5 minutes.
Turn off the heat and add most of the lime juice, holding back a little. Taste and add more of the reserved fish sauce and lime juice to taste.
Stir in chopped cilantro and/or green onions.
Serve on its own or with jasmine rice!

Vegan Modification

Even though chicken is at the heart of this soup ("gai" in tom kha gai means chicken), there is a way to make a vegan version that's still quite satisfying. Here are some simple modifications:

Use vegetable broth instead of chicken. I recommend checking out the veggie stock I made for my mushroom tom yum recipe. I don't recommend Western-style store bought vegetable broth as those tend to have a flavour that doesn't work here.
Instead of chicken, I love using a fun mix of Asian mushrooms. Oyster, shimeji, fresh shiitake, or maitake are all great candidates. Of course you can substitute tofu instead if you like it, and for soup I always recommend fried tofu or tofu puff as they absorb more of the broth than fresh tofu.
Add some tomatoes. Since there's only mushrooms, to add some variety and extra umami, I love to add tomatoes. Using halved cherry tomatoes are better as they are less likely to turn to mush in the soup. The combination of tomato and coconut is divine.
Use soy sauce instead of fish sauce. Or if you have a favorite brand of vegan fish sauce, go ahead and use that.

Shortcut: Making Tom Kha Gai Without Chicken Stock

If you don't have any chicken stock, you can make tom kha gai with water, but obviously you will be giving up some flavour. But there is a trick that will not result in any flavour compromise! Instead of boneless chicken thighs, use chicken drumettes. The bones and collagen will make the broth rich and delicious, you're basically making chicken stock WHILE making the soup itself! The methods will remain the same, but if your drumettes are large you will need to increase the initial simmering time to 20 minutes.

This is the technique I use in my quick and easy tom yum chicken wings recipe, so check that recipe out if you want to see how this technique works!

Frequently Asked Questions

What can I use instead of galangal?

For this dish, nothing. kha means galangal, so you really can't make this soup without it. However, if fresh isn't available, look for frozen galangal which works perfectly, and if needed you can use dried galangal as well.

No, ginger is not a good substitute for galangal. But if you decide to use ginger instead anyway, know that the flavour of the soup is going to be quite different from the galangal version.

Can I make tom kha gai soup in advance?

Tom kha gai is a great soup to make in advance as it keeps well and reheats well. It will last up to a week in the fridge, and it can also be frozen. Ideally you should leave out the lime juice and green onions/cilantro and add them when ready to serve for the best flavour. I'd also put a note on the container to remind yourself to add the lime so you don't forget!

To reheat, you can simply microwave it or reheat it stovetop.