Twelve people took more than 1,000 hours to make the replica caravan which includes working electric lights, seats and a sink with running water.
Organisers of the Motorhome & Caravan Show 2015, where it is on show, said it is the world's largest caravan built with interlocking plastic bricks.
Items made of toy bricks include toothbrushes and a frying pan.
The replica Tab caravan has been put next to a real one at the show.
James Bissett, marketing campaign director for NCC Events, organisers of the show, said: "To get the (Guinness) world record it had to be identical in every way in terms of the size, dimensions, look and functionality.
"Inside you can change the beds and the table as you can in the real thing."
It was unveiled at the show to celebrate 130 years of leisure caravanning this year, with the 2.2m tall and 3.6m long structure featuring "a full interior" according to show organisers.
The Lego brick caravan was certified the world's largest by an official Guinness World Records adjudicator, organisers said.
It is on display at the show until Sunday.
A caravan made from more than 215,000 Lego bricks has been put on display at the NEC near Birmingham.