How to tell if a LEGO® set is fake or another brick brand

Read the listing first

The quickest check takes ten seconds and happens before you message anyone. On 2026-10-06, a Canada-wide Kijiji search for “lego compatible” in Toys & Games returned 244 ads, and almost all of them had “LEGO” in the title. Most of those sellers aren’t hiding anything: they used the word people search for. The trouble starts when the price assumes it’s LEGO brand.

Wording that means it isn’t LEGO brand:

• “LEGO compatible”, “compatible with LEGO”, “compatible avec Lego”, “fits LEGO”
• “Building blocks”, “building bricks”, “blocs de construction”
• “Not LEGO”, “not original”, “off-brand”
• “MOC kit” (a fan design sold as a kit, usually in another brand’s bricks)

Brand names that mean it isn’t LEGO brand. If the description or the box shows another brick brand’s name (Mould King, BlueBrixx, Cobi, Sluban, MEGA Bloks and many others), it is that brand’s product. Plenty of them sell honestly labelled sets, some with their own designs. Just price it as that brand.

Other signals:

• A set number Brickset doesn’t know, or a number that belongs to a different LEGO set.
• “New, no box” for a large, recent set. Genuine sealed sets usually keep their boxes.
• A price far under BrickLink’s used sold price for a big Star Wars, Technic, Icons or Harry Potter set. Check the set’s used price before you message.

If the listing is vague, ask: “Is this LEGO brand? Can you send a close-up photo of the top of a few bricks?” A genuine seller can do that in a minute.

Check the box

A box is the first thing you see at a meetup. Compare it with the set’s photos on Brickset:

• The LEGO logo: the red square with white letters outlined in black and yellow, crisp at the edges.
• The set number in the corner, matching the set name on Brickset.
• Piece count and age mark (“9+”, “18+”), the same as Brickset lists.
• The legal line on the back or bottom, with the LEGO Group’s name and copyright year.
• Print quality: sharp photos, no blurry text, no spelling errors.

A real box doesn’t prove the contents. People sell other brands in genuine LEGO boxes, and sets get mixed. Always check the bricks too.

Check the bricks

1. Look at the studs. Genuine LEGO bricks have the word LEGO moulded on top of almost every stud. Use your phone camera zoomed in, or a magnifier app. Check a dozen random pieces from different bags, not just one.
2. Compare colours. Hold two bricks of the same colour from different bags side by side. LEGO colours match closely; other brands often vary.
3. Feel the clutch. Press two bricks together and pull them apart. LEGO grips firmly and evenly. Too tight, too loose, or uneven from piece to piece suggests another brand.
4. Look underneath. Genuine bricks are cleanly moulded inside, often with a part number. Rough plastic and visible flash (thin excess plastic at the edges) are typical of cheaper moulds.
5. Check transparent parts and Technic pieces. Clear pieces should be clear, not cloudy; Technic pins and gears should turn smoothly and click into place.

Check the minifigures

Minifigures are often where a set’s value sits, and where other parts get swapped in.

• Neck stud. The stud on top of a genuine minifigure’s torso, under the head, carries the LEGO logo.
• Printing. Faces, torsos and legs printed sharply and aligned with the edges.
• Fit. Arms, hands and hips move with even resistance; heads sit firmly.

Some sellers mix genuine bricks with another brand’s figures, or the other way round. Our minifigure guide has the full checks.

Sealed sets

A sealed box is supposed to settle the question, and that is exactly why sealed sets are worth a second look.

• Seals. Look for slits, re-glued flaps or fresh tape. A box opened and resealed may hold anything.
• Shape. Bulging, crushed or re-squared corners suggest it has been opened.
• Weight. If you can compare with another copy, or with a weight from a set database, a big difference is a warning.
• Price. A sealed retired set priced far under its BrickLink new sold price is the classic bait. Check the seller, and never pay a deposit to hold it.

Why there are so many

LEGO designs are widely copied. In 2019, Shanghai police raided Lepin, a manufacturer that copied LEGO designs, and seized about 630,000 products, NPR reported. Plenty of copies were made before that, and they turn up in secondhand bins and on Marketplace. Separately, many brick brands make their own legal products. The issue for a buyer is never the existence of other brands; it is a listing that charges a LEGO price for them.

If you bought a knock-off thinking it was LEGO

1. Message the seller and ask for a refund, in writing, with photos of the studs and the listing wording.
2. Report the listing as misleading on Facebook Marketplace or Kijiji.
3. If the seller insisted it was LEGO and won’t refund, keep the chat and the listing screenshots, and report it to the Canadian Anti-Fraud Centre (or your local fraud reporting service outside Canada).
4. If you paid by card or a method with protection, contact the payment provider. An e-Transfer or cash payment is usually final, which is why the stud check comes before payment.

Where Sift helps

Sift can’t look at the bricks, but it reads every word of the listing on desktop Chrome, Edge and Brave.

• “May not be LEGO brand.” Sift’s LEGO kit flags listings that say “compatible with LEGO”, “LEGO compatible”, “building blocks compatible” or “not LEGO”, and listings that name another brick brand, in English and French.
• Reads the set number and links BrickLink. The first “Check elsewhere” link is BrickLink’s price guide for that set, so a price far under the used average stands out. Google Lens on the listing photo is one more click, useful when a box photo turns up somewhere else.
• Good signs, too. Complete, Minifigs included, Sealed and Instructions show in green when the seller says so.
• Pay-first and off-platform flags when a listing asks for a deposit, an e-Transfer first, or a WhatsApp chat.

The limit: a knock-off described only as “Lego ship” has no wording to flag. On Facebook, the description is read on the listing page, since search cards carry no description. Do the stud check in person either way.

LEGO® is a trademark of the LEGO Group of companies which does not sponsor, authorize or endorse this site. Sift is independent and not affiliated with the LEGO Group, BrickLink or any brick brand named here.