These Lemon Mustard Chicken Thighs are grilled on the barbecue with a zesty marinade of Dijon mustard, whole grain mustard, fresh lemon, oregano and garlic. It's a perfect dish for a summer BBQ with the combination of char from the BBQ and freshness from the lemon mustard marinade. It's easy to make in bulk so it's perfect for a large gathering alongside your favourite sides like BBQ Mediterranean Vegetables or a meal prep throughout your week.

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Why you'll love this recipe
BBQ favourite: These lemon mustard chicken thighs are made for grilling, bringing smoky, charred perfection to your chicken like a BBQ Peri Peri Chicken.
Pair with sides. Serve alongside Mashed Potatoes, a Peach Prosciutto Salad or even a BBQ Asparagus Salad for a summer-themed dinner.
Meal-prep. Barbecues are large so it's easy to cook in bulk for leftovers. Use leftovers in salads like a Turkey Couscous Salad (obviously replacing turkey with chicken), Chicken Macaroni Salad or on a Homemade Bagel.
Citrus. The lemony tang in the marinade adds a bright, fresh flavour alongside other citrus recipes like Lemon Chicken and Orange Roast Chicken. If you prefer something a bit sweeter, try my Honey Mustard Chicken.
Ingredients

Dijon and Wholegrain. I use a combination of both for flavour and texture. Adds a smooth, tangy flavor to the marinade; substitute with yellow mustard for a milder taste. These are preferred over American mustard as they offer more complexity and depth in flavour.
If you don't have wholegrain, substitute with more Dijon.
Lemon. Juice and rind.
Garlic.
Oregano. I use dried for convenience, but you could also use fresh.
Chicken thighs. Boneless is preferred as they won't take as long to cook. You can use bone-in, but they'll take longer to cook so keep an eye on that.
Cornflour. Helps thicken the marinade and creates a light crust when grilled; swap with arrowroot powder if needed.
Please check the recipe card for full list of ingredients and quantity.
How to make BBQ Boneless Chicken Thighs
Step 1: In a large bowl, toss the boneless chicken thighs with cornflour, mustard seeds, salt, and pepper until evenly coated.
Cornflour helps tenderize the chicken and adds a crisp outer texture.
Step 2: In a pan suitable for the BBQ (or in a jar which you'll then transfer onto a pan), whisk together Dijon mustard, wholegrain mustard, lemon juice and zest, garlic, olive oil, dried oregano, salt, and pepper. Add a splash of water to create a smooth, bubbling sauce consistency. Place the pan directly on the BBQ to heat as the chicken cooks.
Step 3: Preheat your BBQ or grill to medium-high heat. Oil the grates well to prevent sticking. Place the chicken thighs skin side down on the grill, cooking for 3–4 minutes to achieve beautiful char marks. Flip the chicken and continue cooking until the exterior is fully white but not fully cooked through.
The searing on high heat allows the moisture to lock in. They'll continue cooking in the sauce.
Step 4: Transfer the partially cooked chicken thighs to the pan with the bubbling lemon mustard sauce. Let the chicken simmer in the sauce for 8–10 minutes, turning occasionally to coat. The cornflour on the chicken will naturally thicken the sauce as the chicken cooks through.
Step 5: Once the chicken reaches 69°C (160°F) remove the chicken thighs from the pan and let them rest for 5 minutes before serving (they'll continue to rise to 74°C (165°F).
Step 6: Drizzle the thickened sauce over the chicken and serve with your favourite sides, such as roasted vegetables or a fresh salad.
Top Tip
Patience for the Char Marks: When grilling the chicken skin-side down, don’t move it around too soon. Allow it to sear for 2–3 minutes to get those beautiful char marks before flipping.
Check Your BBQ Heat: Ensure your BBQ is at medium-high heat before grilling to avoid over-charring the chicken and maintain juicy tenderness. If the temperature isn't hot enough when you add the chicken on, they may stick to the grates.
Variation: make in the oven
Oven. If you don't have a BBQ (or the weather isn't suitable for the BBQ), you can make these in the oven by baking at 180°C (360°F) for 20 minutes and then finishing with the sauce in a pan.
How to make chicken a meal prep?

I meal prepped these lemon mustard chicken thighs alongside whole potatoes (also cooked on the BBQ) and peas to ensure I was hitting all the macros. The Dijon mustard lemon sauce from the chicken seeps into the potatoes and peas when reheated and was such a delicious dish!!
You can store the cooked chicken thighs, potatoes, and peas in separate airtight containers in the fridge for up to 3–4 days. Keeping them separate prevents the sauce from soaking into the potatoes and maintains their texture. That's why you can see the potatoes still wrapped up in their foil (but you'll need to remove this when reheating).
How to make chicken a meal prep?
Reheat the chicken thighs in a pan over medium heat, adding a splash of water or stock to loosen the sauce if it’s thickened.
If you're having this as a meal prep, you can heat all of the ingredients in the microwave (make sure to remove the aluminium foil from the potatoes) on 1 minute intervals. I suggest flipping the thigh over each interval to ensure it heats all the way through (this should take 3-4 minutes).
Freezing BBQ chicken thighs
The chicken thighs can be frozen with the sauce in a freezer-safe container or bag for up to 3 months. Keep these whole when freezing and with the sauce as this helps the thighs retain their moisture, making the texture better when reheating. Thaw in the fridge overnight before reheating.
If you want more meal prep information, check out my Meal Prep for Beginners post and my Meal Prep Basics E-Book.
FAQs
Boneless chicken thighs should be cooked to an internal temperature of 74°C (165°F) for safe consumption. This ensures the chicken is fully cooked while remaining juicy and tender. Use a meat thermometer to check the thickest part for accuracy.
I normally cook until 69°C (160°F) and then let them rest for another 5-10 minutes. The temperature will increase during that time, and the fibres in the chicken will loosen to ensure its moist and not dry.
Barbecuing boneless chicken thighs typically takes 6–8 minutes per side over medium-high heat, depending on their thickness. Start by grilling skin-side down for char marks, then finish in a pan with sauce or on indirect heat to ensure even cooking and prevent burning.
Yes! This sauce is versatile and works wonderfully with Pork, Salmon, Barramundi or even tofu for a vegetarian option. Adjust cooking times based on the protein you choose and size of the cut.
Other chicken recipes you'll like
Or, you can have a browse through my Chicken Category for more delicious eats.
Recipe

Barbecue Boneless Chicken Thighs (with Lemon Mustard sauce)
Equipment
Ingredients
Lemon Mustard Sauce
- 30 g (2 tbsp) Dijon mustard see note 1
- 30 g (2 tbsp) wholegrain mustard see note 1
- 1 lemon (approx. 60 ml / 4 tablespoon juice + zest)
- 2 cloves garlic minced
- 10 g (1 tbsp) dried oregano
- Salt and pepper to taste
- Water as needed for consistency
Chicken
- 500 g (1.1 lbs, approx 6) chicken thighs boneless
- 15 ml (1 tbsp) olive oil extra for grilling
- 15 g (2 tbsp) cornflour
- 15 g (2 tbsp) mustard seeds optional
- Salt and pepper to taste
Serve with (optional)
- 5 potatoes washed + cooked (see note 3)
- 500 g (3 cups) green sweet peas cooked as desired (see note 4)
Instructions
- Toss the boneless chicken thighs in a large bowl with cornflour, mustard seeds, salt, and pepper until evenly coated.
- In a separate bowl (or a BBQ safe pan) whisk together Dijon mustard, wholegrain mustard, lemon juice and zest, garlic, olive oil, oregano, salt, and pepper. Add water for a smooth sauce consistency. Place the pan on the BBQ to heat as the chicken cooks.
- Preheat the BBQ to medium-high and oil the grates. Grill the chicken thighs skin side down for 3–4 minutes to achieve char marks. Flip and cook until the exterior turns white but is not fully cooked through.
- Transfer the chicken to the bubbling lemon mustard sauce on the BBQ. Simmer for 8–10 minutes, turning occasionally. The cornflour will naturally thicken the sauce as the chicken cooks.
- Once the chicken reaches 69°C (160°F), remove it from the pan and let it rest for 5 minutes to reach 74°C (165°F).
- Drizzle the thickened sauce over the chicken and serve with your favourite sides. See post for specific meal prep information, including how to store and reheat
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