Does Lego Junior Work with Duplo? (Or Legos?)

Do Lego Junior Work with Duplo?

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Legos are one of the most popular toys for children in the United States and all around the world.

Lego has been around for decades, during which they have created several toy lines for all ages not just older ones. 

There are a lot of parents that are apprehensive about giving their kids complicated Lego sets with tons of small pieces, which is where Lego Junior and Lego Duplo come into play.

These Legos are specifically designed for young children and can help them develop creativity and motor skills while also being big enough that they can’t swallow them. 

However, the question a lot of people have is if the two can be used together?

Lego Junior and Lego Duplos are compatible with each other as well as with regular Legos too. All of the official Lego, Duplo, and Lego Junior blocks can all be built on each other and all of them are interchangeable. 

What this means is that even as your children get older they can continue to build using their Duplos and Lego Junior sets while also adding Legos to the mix as well. 

This way they can build bigger and better designs using either Duplos or Lego Juniors as the base or as their own separate part of the city, town, etc. that they are building. 

The Lego company made all of the products work together to build on each other except for a few off the odd shaped Legos, a few minifigures, and the 1×1 bricks (they are too small to fit on a Duplo/Lego Junior’s studs. 

To see some of the most popular Lego Juniors sets available you can click here.

How to Use Lego Juniors with Lego Duplos

Since Lego Juniors are just another version of the standard Lego sets, they are entirely compatible with Lego Duplo blocks.

As long as the Lego Duplo blocks have hollow studs, you’ll be able to attach regular Legos or Lego Juniors to the larger Duplo blocks.

If you have a Duplo base plate (these have solid studs), you will only be able to attach more Duplo blocks to it. In most cases, Duplo blocks will be able to fit onto Lego baseplates, but only if they are the standard rectangle shape.

There are also a few pieces that won’t be compatible if you have a regular Lego set and a Lego Duplo set. Most important is how many studs are on each edge of the Lego brick. As long as the number is even and not odd, the bricks will fit together without any issue. 

The even number of studs is important because Lego Duplos fit with Lego bricks at a ratio of 1:2. So a 2×2 Lego brick fits on top of a single Duplo stud. However, a 2×3 Lego brick is too small to fit over two Duplo studs, but too large to fit over one.

It’s also important to remember that because of their size differences, connections between Duplo and Lego bricks can be less stable than their connections to blocks of the same type even though they will fit. 

In practice, this typically means that many children will use the Duplos and Lego Juniors as their base part of the build and then build the more intricate details using Legos. 

Some people might also use Duplos and Lego Junior blocks to build the largest structures and then use the normal Legos for the smaller ones. 

Ultimately, the only limit is your imagination. 

Places to Buy Lego Junior and Duplos

Because Legos are such a popular toy around the world, there is no shortage of places to buy them from. Here is a short list of some of the most popular places to get both Duplos and Lego Junior blocks. 

The Lego Store

In some cities, there are physical Lego stores that serve as both shopping centers and tourist attractions.

The good thing about going to a Lego store for your Lego Junior or Lego Duplo sets is that they’ll probably have a lot of variety in their sets and they’ll have all of the newest sets as soon as they come out as well. 

The downside is that the tourism aspect can make them crowded and more expensive. To avoid that, you can shop on the Lego website for even more inventory range and variety.

Target, Walmart, and Other Big Retail Chains

Target and Walmart are some of the biggest and most popular retail chains in America. They have extensive toy sections where you can find a large range of both Lego Junior and Lego Duplo sets.

One benefit of shipping at Walmart, Target, etc. is that they will often clearance out less popular sets at certain times of the year meaning you can often pick up Legos, Duplos, and Lego Juniors at a significant discount. 


Amazon is where most online shopping searches start in the modern era. You can find all sorts of Lego sets on the website for whatever price point you’re looking for.

The largest benefit to buying on Amazon is that you never even have to leave your house and you can also have the Legos sent directly to yourself or someone who you are giving them to. 

You will also find the largest possible variety of Lego Junior blocks and Duplos on Amazon as well. 

What are Lego Junior blocks? 

Lego Juniors were first launched officially in 2014. However, the Lego Junior branding was discontinued in 2018.

They were originally designed to help children transition from using the preschool Lego sets into using the regular sets.

Unlike other special Lego sets, Lego Junior blocks were designed specifically for children between the ages of four and seven. They were made as basically simplified versions of regular Lego sets so that young kids don’t have trouble with small, multipurpose pieces.

Lego Juniors sets have simplified pieces and instructions that make it easy for young kids to assemble on their own and help them develop some independence.

There were a total of 66 different Lego Junior sets made before the official branding was discontinued. The sets mostly consisted of branded character sets like Star Wars, Cars, and Harry Potter. However, Lego Juniors haven’t completely disappeared.

Since 2018, the sets formerly branded as Lego Junior have been integrated into the regular Lego branding. They’re now simply labelled as Legos for ages four and over.

What is Lego Duplo?

Lego Duplo has been around for much longer than Lego Junior and is still being sold and marketed to kids and parents today.

The Lego Duplo blocks are bigger than the regular or junior Legos for a couple of different reasons.

The first is that they need to be safe for children that are three or older. Duplo blocks are made for young children and toddlers between the ages of 36 months and 5 years so they have to be extremely safe. 

Naturally, regular Legos have a lot of small pieces that can be a choking hazard for kids who are younger than three.

The second reason for the larger blocks is that they are made to be easier for younger children to build with. The larger blocks are easier to handle and also help toddlers develop their fine motor skills without overwhelming them.

Unlike Lego Junior, Lego Duplo encompasses more than just branded character sets. They also have many more general sets, encompassing more than 1000 total sets.

Lego Duplo has been a part of the Lego brand since the late 1960s, and they have continually been one of the most popular ways to introduce toddlers to playing with Legos.


Lego Junior and Lego Duplo are both great for kids to develop their creativity, fine motor skills, and independence.

Lego Duplo blocks are for the youngest kids and toddlers, who can then transition to using Lego Junior sets and eventually standard Lego sets.

Luckily, you don’t have to throw your Duplo sets out once your child wants to start using Lego Juniors (or Legos) as they can be integrated and used together without too much difficulty and with rare exceptions. 

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