Sheet Pan Beef Fajitas for Quick Weeknight Dinners

Sheet pan dinners are a simple, flavorful solution for busy weeknights—one pan, minimal cleanup, and a satisfying meal in about 30 minutes. These easy sheet pan beef fajitas are a low-carb, budget-friendly option that come together quickly and taste great for family dinners or meal prep.

This sheet pan beef fajita recipe uses flank steak, sweet peppers, and red onion tossed with a smoky, slightly spicy spice mix. Roast everything together until the vegetables are tender and the meat is cooked through, then finish with fresh cilantro and lime. Serve in tortillas, lettuce wraps, or over cauliflower rice for an easy low-carb meal.

Easy Sheet Pan Beef Fajitas Ingredients

• 1 1/2 pound flank steak, sliced into thin strips
• 1 pound mini sweet peppers, halved lengthwise and seeded
• 1 large red onion, thinly sliced
• 2 tablespoons extra virgin olive oil
• 1 tablespoon ground cumin
• 2 teaspoons chili powder
• 1/2 teaspoon cayenne pepper
• 1 teaspoon red pepper flakes
• Pink salt and black pepper, to taste
• 1/2 cup fresh cilantro leaves, roughly chopped
• 1 large lime, sliced

Optional:

• 1 large avocado, diced
• Keto corn tortillas or low-carb flour tortillas
• Large lettuce leaves for wraps

Easy Sheet Pan Beef Fajitas Instructions

1. Preheat the oven to 400°F (200°C). Line a large rimmed baking sheet with parchment paper or a silicone baking mat.
2. In a large bowl, combine the sliced flank steak, halved peppers, and sliced red onion. Add the olive oil, cumin, chili powder, cayenne, and red pepper flakes. Season generously with salt and black pepper and toss until everything is evenly coated.
3. Spread the steak and pepper mixture in a single layer on the prepared baking sheet. Roast for 15–20 minutes, stirring once if needed, until the steak reaches your desired doneness and the peppers are softened and slightly caramelized.
4. Remove from the oven, sprinkle with chopped cilantro and a squeeze of lime. Serve immediately with diced avocado, tortillas, or lettuce leaves for a low-carb option. Enjoy.

Tip: If available, use a three-quarter sized sheet pan rather than a standard half sheet (13″ x 18″) so the ingredients can spread out in a single layer and roast evenly without overcrowding.

Easy Sheet Pan Beef Fajitas Nutrition

Serves 8

Calories 174; Total Carbs 6.5 g; Fiber 1.3 g; Net Carbs 5.2 g; Sugars 2.2 g; Fat 8.2 g; Protein 19.1 g

Prep, Storage and Reheating

Can I prep sheet pan fajitas ahead of time? Yes—assemble the seasoned steak and vegetables and store them covered in the refrigerator until you’re ready to roast. This saves time on busy nights.

How do you store leftover fajitas? Keep leftovers in an airtight container in the refrigerator for up to three days. They can also be frozen for longer storage; thaw and reheat before serving.

How do you reheat beef fajitas? Reheat slices in a microwave-safe dish until warm, or refresh in a preheated oven at 350°F (175°C) for about 10–15 minutes until heated through.

Substitutions and Toppings

What can I use instead of a sheet pan? If you don’t have a sheet pan, a large oven-safe baking dish or roasting pan will work—just avoid overcrowding so everything roasts rather than steams.

What are some great fajita toppings? Popular options include fresh cilantro, a squeeze of lime, diced avocado or guacamole, shredded lettuce, sour cream, and sliced jalapeños. Mix and match toppings to suit your taste.

Below are a few photos from the recipe process.

Printable recipe card: