Introduction

If you’re looking for a low-effort, high-reward keto-friendly dinner that the whole family will love, this Keto Sheet Pan Chicken Fajitas recipe is exactly what you need. It’s colorful, full of zesty Tex-Mex flavor, and cooked on a single baking sheet, making it an ideal weeknight meal for anyone on a ketogenic or low-carb diet.

Sheet pan meals are a lifesaver when it comes to meal prep, cleanup, and flavor infusion. In this recipe, juicy chicken breast is sliced and marinated in a bold blend of spices, then roasted with colorful bell peppers and red onions until everything is perfectly tender and caramelized. The result? A sizzling-hot, restaurant-style fajita experience—minus the carbs.

Whether you’re cooking for one or feeding a crowd, this dish is fully customizable, macro-balanced, and packed with healthy fats and protein. Serve it in lettuce wraps, low-carb tortillas, on top of cauliflower rice, or in a fajita bowl with avocado and sour cream. The options are endless, and the cleanup is minimal.

Why You’ll Love This Recipe

  • 🌱 Naturally low in carbs and gluten-free
  • 🍗 High in protein and healthy fats
  • 🧄 Bursting with bold, Mexican-inspired flavors
  • 🥗 Perfect for meal prep and batch cooking
  • 🧼 One pan means quick and easy cleanup
  • 🔥 Ideal for baking or grilling
  • 🧊 Freezer-friendly and reheats beautifully

Ingredients

For the Chicken and Vegetables:

  • 1 ½ pounds boneless, skinless chicken breasts, sliced into ½-inch strips
  • 1 large red bell pepper, sliced thin
  • 1 large green bell pepper, sliced thin
  • 1 large yellow bell pepper, sliced thin
  • 1 medium red onion, sliced into wedges
  • 2 tbsp olive oil or avocado oil

Fajita Seasoning Blend:

  • 1 tbsp chili powder
  • 1 ½ tsp smoked paprika
  • 1 tsp ground cumin
  • ½ tsp garlic powder
  • ½ tsp onion powder
  • ¼ tsp dried oregano
  • ¼ tsp black pepper
  • ½ tsp sea salt
  • ¼ tsp crushed red pepper flakes (optional, for heat)
  • Juice of 1 fresh lime (about 2 tbsp)

Garnishes and Serving Suggestions:

  • Fresh cilantro, chopped
  • Sliced avocado or guacamole
  • Shredded cheddar cheese or Monterey Jack
  • Sour cream or full-fat Greek yogurt
  • Lime wedges for serving
  • Low-carb tortillas or romaine lettuce leaves for wraps

Instructions

Step 1: Preheat the Oven

Preheat your oven to 425°F (220°C). Line a large sheet pan with parchment paper or aluminum foil for easy cleanup. Lightly grease with nonstick spray or brush with a small amount of oil.

Step 2: Slice Chicken and Vegetables

Thinly slice the chicken breasts into long, even strips, about ½-inch thick. Do the same with all your bell peppers and the red onion. The more consistent your cuts, the more evenly everything will cook.

Step 3: Make the Seasoning Blend

In a small bowl, mix together all of the dry spices: chili powder, smoked paprika, cumin, garlic powder, onion powder, oregano, salt, black pepper, and red pepper flakes. Stir well to combine.

Step 4: Toss Chicken in Marinade

In a large mixing bowl, add the sliced chicken. Drizzle with 1 tablespoon of olive oil and the juice of one lime. Sprinkle half of the spice blend over the chicken and toss to coat thoroughly.

Step 5: Season the Vegetables

In another bowl, add your sliced bell peppers and onions. Drizzle with the remaining olive oil and sprinkle the remaining half of the fajita seasoning blend. Toss well until vegetables are evenly coated.

Step 6: Arrange on Sheet Pan

Spread the seasoned chicken strips evenly on one side of the prepared sheet pan. Add the vegetables to the other side. If you prefer everything to cook together, mix them before arranging, but keeping them separate helps control doneness.

Step 7: Roast to Perfection

Bake for 20–25 minutes, flipping the chicken and tossing the vegetables halfway through. For extra browning, turn the oven to broil for the last 2–3 minutes, but watch closely to prevent burning.

Step 8: Rest and Garnish

Once cooked, remove the pan from the oven. Let everything rest for 3–5 minutes. This helps the juices settle and keeps the chicken moist. Sprinkle with freshly chopped cilantro and an extra squeeze of lime.

Step 9: Serve Your Way

Serve your chicken fajitas immediately with your choice of toppings. For a classic approach, use low-carb tortillas. For ultra-low-carb, scoop them into lettuce wraps or serve over cauliflower rice or shredded cabbage.


Nutritional Information (Per Serving – Based on 4 Servings)

  • Calories: 320
  • Fat: 17g
  • Protein: 35g
  • Total Carbs: 9g
  • Fiber: 3g
  • Net Carbs: 6g
  • Sugar: 4g (from vegetables)

WW SmartPoints: 4 per serving
(Calculated using chicken breast, olive oil, vegetables, and spices. Adjust for toppings or tortillas.)

Meal Prep and Storage Tips

  • Refrigerator: Store leftovers in an airtight container for up to 4 days.
  • Freezer: Freeze cooked chicken and vegetables for up to 2 months. Reheat gently to avoid drying out the chicken.
  • Reheat: Microwave in 30-second bursts or warm in a skillet over medium heat with a touch of oil.

Variations and Substitutions

  • Chicken thighs can be used for more fat and flavor.
  • Beef fajitas: Substitute flank steak or sirloin, sliced thinly.
  • Shrimp fajitas: Bake shrimp separately for only 8–10 minutes.
  • Extra vegetables: Add zucchini, mushrooms, or jalapeños for variety.
  • Dairy-free: Skip the cheese and sour cream; use avocado and salsa.

Tips for Best Results

  1. Slice everything evenly to ensure uniform cooking.
  2. Use fresh lime juice—it enhances the seasoning and tenderizes the chicken.
  3. Broil for added char for that restaurant-style flavor.
  4. Let meat rest before serving to retain juices.
  5. Use pre-cut vegetables for an even quicker meal prep option.

Make It a Full Keto Meal

Serve your sheet pan fajitas over:

  • Cauliflower rice sautéed in lime and cilantro
  • Keto tortillas made with almond or coconut flour
  • Shredded lettuce or cabbage for fajita bowls
  • Avocado mash or guacamole for healthy fats

Common Questions

Can I make this ahead of time?

Yes! You can prep the chicken and veggies with the seasoning and store them in the fridge for up to 24 hours before baking.

Is this dish spicy?

It has a mild to moderate heat. Adjust the chili powder and red pepper flakes to your taste preference.

What’s the best way to reheat this?

Reheat in a skillet with a splash of olive oil or in the microwave for a quick lunch. Avoid overcooking to keep the chicken juicy.

Final Thoughts

This Keto Sheet Pan Chicken Fajitas recipe is everything you want in a weeknight dinner—quick, low-carb, full of flavor, and incredibly versatile. It’s a great meal prep option, family-friendly, and endlessly customizable. From busy weeknights to taco Tuesdays, this sheet pan meal delivers on taste, nutrition, and simplicity.

Best of all, it’s naturally gluten-free, dairy-optional, and made entirely with whole food ingredients that align with the ketogenic way of eating. Whether you’re new to keto or a seasoned low-carb eater, this recipe is a guaranteed winner you’ll want to make again and again.