Roasted Leg of Lamb Bone-In with Lemon, Garlic and Rosemary

When I think of a celebratory meal, the first dish that comes to mind would be leg of lamb! Many people may think of a turkey instead, but for me that’s not the case anymore. Don’t get me wrong, I love turkey and we eat a lot of turkey on a regular basis since my husband is a hunter. So it is a common item on our dinner table which is why it is now unimpressive to us and not so special!

How do you feel about roasting a leg of lamb? To some, it may sound a little intimidating.  But the fact is that a leg of lamb is actually one of the easiest cuts of meat to cook. And if you try my roasted leg of lamb recipe, seasoned with garlic, lemon and rosemary, you will have fall-off-the-bone perfect lamb roast every time. You will be pleasantly surprised just how flavorful your lamb will be with just a few simple ingredients you probably already have in the kitchen.

whole roasted leg of lamb

What better way to impress your guests at your next dinner party than to showcase a lamb as your table centerpiece. This recipe is simply delicious and is a crowd pleaser.  It’s a great main dish to serve at your next holiday dinner or whenever a lamb craving strikes.  I hope you try and enjoy it as much as my family does.

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What equipment Will I Need to Roast the Leg of Lamb?

  • a large enough roasting pan with a rack such as the one below
  • A lid for the roasting pan or you can use aluminum foil for tenting the roast
  • Instant read thermometer

Should I Marinade the Leg of Lamb?

Lamb itself is a very tender meat and you technically do not need to marinate it. However, if you prefer to, I would not marinate a leg of lamb for more then 2-3 hours. If you marinate it for more than that it can destroy the integrity of the meat and change the texture and flavors, making it chewy and tough.

For best results, I recommend that you simply take all the ingredients for the lamb roast and rub it well into the lamb and let it rest until it reaches room temperature before placing it in the oven.

At What Temperature Should I Roast the Leg of Lamb?

I recommend starting off with a higher oven temperature and then reducing it after 20 minutes. This sears the meat and locks in all the juices.

For this recipe, I would start off by getting the oven to 420 degrees F and roasting the leg of lamb uncovered for 20 minutes. After 20 minutes on high heat, cover the roast and reduce the temperature to 375 degrees F and continue cooking for 1 hour. Once the hour is up, take the roast out of the oven, uncover it and take the internal temperature of the roast. Refer to the internal temperature guide below for doneness.

sliced leg of lamb

What is the Cooking Time for Roasted Leg of Lamb Bone-In?

Determining how long it takes to cook your lamb depends on whether you prefer to eat your lamb when its rare, medium, or well done. I personally cannot stand a piece of bloody meat on my plate, so I like my meat medium-well done.

Here is a recommended guide chart by the USDA of internal temperatures to determine when your lamb is done (with oven roasting temperature of 375 degrees F):

Rare 125 degrees F 
Medium-Rare 135 degrees F
Medium 135 – 140 degrees F
Well-Done 155 – 165 degrees F

What Should I Serve with the Leg of Lamb?

There are some people who really like their lamb with a side of mint jelly. Sometimes I’ll just get a jar from the supermarket because I personally don’t eat enough mint jelly to bother myself with making it from scratch.

If you are looking for side dishes to serve along with this leg of lamb, my family’s personal favorite sides for this meal would be my Cilantro Lime Rice and Creamy Mint Peas. These sides are super easy and quick to make while the leg of lamb is roasting in the oven.

sliced leg of lamb on a platter on a bed of spinach

How Should I Store My Leftovers?

Allow the lamb to cool completely first.  Then place the carved lamb pieces in an airtight container and store it in the fridge. It should last for up to 4 days.

Yield: Serves 8 to 10 people

Roasted Leg of Lamb Bone-In with Garlic, Lemon and Rosemary

roasted and sliced leg of lamb

Roasted leg of lamb with bone-in and seasoned with garlic, lemon and rosemary

Prep Time 15 minutes
Cook Time 1 hour 30 minutes
Total Time 1 hour 45 minutes


  • 6 lb fresh leg of lamb
  • 6 cloves of garlic
  • 4 tbsps Dijon mustard
  • ¼ cup lemon juice
  • ¼ cup of olive oil
  • 3 tbsps dried oregano
  • 3 springs of fresh rosemary
  • 1 tbsp kosher salt or to taste
  • 1 tsp black pepper


  1. Take leg of lamb out of the fridge and place it in the roasting pan on the rack.
  2. Rub oil, lemon juice and Dijon mustard over the leg of lamb evenly.
  3. Season it well with salt, pepper, oregano and fresh rosemary.
  4. Let the leg of lamb sit on the counter like this for 1-2 hours so it reaches room temperature.
  5. Preheat oven to 420 degrees F
  6. Place leg of lamb in the oven uncovered for 20 minutes.
  7. Reduce the heat to 375 degrees F, cover the lamb and cook for 1 hour.
  8. After an hour of cooking, pull the lamb out and check for doneness using a thermometer insert (insert in the thickest part of the leg without touching the bone).
  9. Lamb is done once the internal temperature reads 135 degrees F (note: lamb will continue to cook internally for 15 minutes after taking it out of the oven).
  10. If roast has not reached the recommended internal temperature, return the lamb back to the oven uncovered and cook for another 20 minutes (keep checking the roast ever 20 minutes until done to your liking).
  11. Once it’s done, let it rest for 15 minutes before carving.

roasted and sliced leg of lamb, pictured for a pinterest pin

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