This easy, healthy chicken zucchini casserole is perfect for a fast weeknight meal, and you only have to dirty one pan! Made with fresh zucchini, tender chicken breast, a quick and simple pesto San Marzano tomato sauce, and cheese, it’s baked in the oven until golden brown and bubbly. {Gluten-free & Low Carb}

Chicken Zucchini Tomato Casserole – Easy One Pan Meal!
Casseroles are such a perfect meal for busy weeknights! They can be assembled in advance, making it easy to just pop the casserole dish in the oven after work or sports practice.
This chicken zucchini casserole recipe is loaded with healthy ingredients, like chicken and fresh veggies, that taste fantastic covered in sauces and molten cheese. So good!

Why We Love This Chicken Zucchini Bake
- Delicious: This easy casserole recipe has wonderful flavor from the San Marzano tomatoes and pesto. If you’re lucky enough to have leftovers, your family will be fighting over them!
- Family-friendly: Your whole family will fall in love with the layers of flavor in this budget-friendly casserole! Plus, it can be served up with rice, pasta, quinoa or on its own, so it’s easily customizable!
- Make ahead: You can easily assemble this chicken zucchini tomato casserole on the weekend or in the morning, and just pop this easy dinner recipe in the oven! It’s a great way to ensure you’re feeding your family a healthy meal without the mess and stress.
Ingredient Notes

- Chicken breast: Cube fresh boneless skinless chicken breasts, tenderloins, or chicken thighs for easy prep work. You can also use leftover chicken from a rotisserie chicken.
- Seasonings: You’ll need just a few seasonings for tons of flavor, including kosher salt, freshly cracked black pepper, and Italian seasoning.
- Olive oil: Use a little olive oil to precook all of the veggies and chicken for less time in the oven.
- Vegetables: This chicken zucchini casserole with tomato has lots of fresh veggies, including zucchini, yellow squash, yellow onion, and fresh garlic.
- San Marzano whole tomatoes: How can so one can contain so much flavor? These are truly the best canned tomatoes, and they give this chicken zucchini casserole recipe real Italian flavor.
- Pesto sauce: Made by blending fresh basil with parmesan, pine nuts, and olive oil, pesto is loaded with flavor and will bring the rest of the ingredients together. You can use store-bought or prepare some homemade pesto.
- Cheese: The best casseroles are cheesy, and this one has a delicious crust of delicious parmesan cheese and mozzarella cheese.
How to Make Chicken Zucchini Casserole – Step-by-Step Instructions
Step 1: Cook the Veggies + Chicken


- Preheat oven to 425℉. Pat chicken pieces very dry with a paper towel.
- Heat a heavy, oven safe large skillet over medium high heat, add a drizzle of olive to coat the bottom of the pan. Add the zucchini, yellow squash, and onion. Saute until onions are translucent, squash is tender, and they have started to brown, about 5-8 minutes. Remove to a bowl and set aside.
- Add another drizzle of olive oil, followed by the chicken. Season chicken with a sprinkle of salt. Saute chicken, flipping occasionally, until golden brown on all sides and almost cooked through, about 5-8 minutes. Remove to a bowl and set aside.
Step 2: Prepare the Sauce



- Reduce heat to medium, add a drizzle of olive oil if needed, followed by the garlic. Saute until garlic is translucent, about 1 minute. Add in the canned tomatoes, Italian seasoning, pesto, and a generous pinch of salt and pepper.
- Using the back of a spoon or a potato masher, start breaking up the tomatoes until they integrate into the sauce. Simmer sauce for 15 to 20 minutes until reduced and thickened. When you pull a wooden spoon across the bottom of the pan, the sauce should spread back out very slowly.
Step 3: Assemble Casserole + Bake




- Add the chicken back to the pan on top of the sauce, then place the zucchini mixture on top of the chicken, and sprinkle with the cheese.
- Bake in the preheated oven for 15-20 minutes or until the cheese is melted and bubbly. Serve hot with quinoa, rice or pasta.
To Prepare in Baking Dish
- Follow the recipe as directed, using a large heavy skillet. Grease a 2 quart baking dish. Layer the sauce, chicken, and zucchini in the prepared baking dish and bake as directed.
Keep scrolling to the recipe card below for the full printable recipe!
Recipe Tips:
- Feel free to use any combination of tender squash and/or zucchini.
- This recipe was developed using Barilla jarred pesto, but feel free to sub in your own favorite store-bought or homemade pesto.
- San Marzano tomatoes are imported from Italy, and are exceptionally sweet, with low acidity. They are readily available at most large grocery stores.
- If you can’t find San Marzanos, use the best canned tomatoes you can find. If your sauce is too acidic after cooking down, stir in ¼ tsp baking soda to neutralize the acid. You can also add a pinch of sugar if needed.

Recipe FAQs
Since squash is so high in moisture, it’s best to either press your pieces of zucchini between a kitchen towel or precook them. In this zucchini chicken casserole, you’ll sautee your zucchini slices in olive oil with a little onion and garlic. This adds flavor to each bite and will help the zucchini release excess moisture before you add it to the casserole.
This is a really easy recipe to adapt to a dairy-free lifestyle. You can either eliminate the cheese topping or use plant-based cheeses. Pestos typically contain Parmesan cheese, so either make your own dairy-free pesto by blending basil with olive oil and pine nuts, cashews or walnuts or purchase a dairy-free pesto.
The great thing about this easy recipe is that it’s so adaptable. You can really add as many spices and seasonings as you’d like. Feel free to scour your spice cupboard for garlic powder or even red chili flakes for a little heat. If you have some tomato paste on hand, add a tablespoon to the tomato mixture for extra flavor! Tweak it to suit your preferences as much as you’d like.
Storage Guidelines
Refrigerator: Store leftover zucchini casserole in an airtight container in the fridge for 3-5 days. To reheat, either microwave for 3-4 minutes or bake in the oven at 350 for 5-10 minutes or until fully warmed.
Freezer: If you have too much leftover, you can freeze individual portions to enjoy later. The zucchini may be even softer after freezing, but the flavors will still be great. Be sure to let the dish cool to room temperature, then chill the servings in the fridge before freezing. Frozen leftovers will last 1-3 months. Let them thaw overnight in the fridge before reheating.

What to Serve with Zucchini Casserole
This low carb chicken zucchini casserole is a complete meal on its own. It contains protein, fats, and carbohydrates to nourish your entire family. For even more fibre, serve it with a bowl of cauliflower rice, brown rice, pasta or quinoa.
It’s also lovely with a tossed green salad full of fresh veggies, like tomato, cucumber, green onion, and red onion. Or try out this Greek Cucumber Noodle Salad. It tastes amazing paired with this casserole and has such a refreshing flavor!
Recipe Variations
- Switch up the protein: Chicken tenderloins or turkey breast can also be used instead of chicken breast.
- Add more veggies: This is a great recipe to adapt with even more fresh veggies. Try adding thick slices of fresh tomato, eggplant, mushrooms, red bell pepper, and more.
- Sprinkle breadcrumbs: For a crispy, crunchy topping, sprinkle panko or Italian breadcrumbs on top of the cheese. This will add a little crunch and texture for a fun eating experience!

More Similar Recipes
- Easy Chicken Burrito Casserole
- Crockpot Mexican Casserole
- Healthy Zucchini Fritters
- Chicken Zucchini Poppers
- Zucchini Turkey Burgers
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Healthy Chicken Zucchini Casserole
Ingredients
- 1 1/2 pounds boneless skinless chicken breast cubed
- Kosher salt
- Freshly cracked pepper
- Olive oil
- 1 small zucchini thinly sliced
- 1 small yellow squash thinly sliced
- 1 small yellow onion chopped
- 3 cloves garlic minced
- 28 ounce can San Marzano whole tomatoes
- 1/4 cup pesto sauce
- 1 teapoon Italian seasoning
- 1/2 cup freshly grated parmesan cheese
- 1 cup shredded mozzarella cheese
Optional for serving
- Cooked rice, pasta or quinoa
Instructions
- Preheat oven to 425℉. Pat chicken pieces very dry with a paper towel.
- Heat a heavy, oven safe large skillet over medium high heat, add a drizzle of olive to coat the bottom of the pan. Add the zucchini, yellow squash, and onion. Saute until onions are translucent, squash is tender, and they have started to brown, about 5-8 minutes. Remove to a bowl and set aside.
- Add another drizzle of olive oil, followed by the chicken. Season chicken with a sprinkle of salt. Saute chicken, flipping occasionally, until golden brown on all sides and almost cooked through, about 5-8 minutes. Remove to a bowl and set aside.
- Reduce heat to medium, add a drizzle of olive oil if needed, followed by the garlic, saute until garlic is translucent, about 1 minute. Add in the canned tomatoes, Italian seasoning, pesto, and a generous pinch of salt and pepper.
- Using the back of a spoon or a potato masher, start breaking up the tomatoes until they integrate into the sauce. Simmer sauce for 15 to 20 minutes until reduced and thickened. When you pull a wooden spoon across the bottom of the pan, the sauce should spread back out very slowly.
- Add the chicken back to the pan on top of the sauce, then place the zucchini mixture on top of the chicken, and sprinkle with the cheese.
- Bake in the preheated oven for 15-20 minutes or until the cheese is melted and bubbly. Serve hot with quinoa, rice or pasta.
Notes
- To bake in a baking dish instead: Follow the recipe as directed, using a large heavy skillet. Grease a 2qt. baking dish. Layer the sauce, chicken, and zucchini in the prepared baking dish and bake as directed.
- Chicken tenderloins may be used in place of breasts.
- Feel free to use any combination of tender squash and/or zucchini.
- This recipe was developed using Barilla jarred pesto, but feel free to sub in your own favorite store-bought or homemade pesto.
- San Marzano tomatoes are imported from Italy, and are exceptionally sweet, with low acidity. They are readily available at most large grocery stores.
- If you can’t find San Marzanos, use the best canned tomatoes you can find. If your sauce is too acidic after cooking down, stir in ¼ tsp baking soda to neutralize the acid. You can also add a pinch of sugar if needed.
- Store leftovers in an airtight container in the fridge for up to 3-5 days.
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