Antwerp's diamond district, also known as the Diamond Quarter (Diamantkwartier), and dubbed the Square Mile, is an area within the city of Antwerp, Belgium. It consists of several square blocks covering an area of about one square mile. While as of 2012, much of the gem cutting and polishing work historically done in the neighborhood had moved to low wage centers elsewhere, about 84% of the world's rough diamonds passed through the district, making it the largest diamond district in the world with a turnover of 54 billion dollars. Each year, approximately 50% of the rough diamonds return to Antwerp for cutting and polishing.

The Antwerp diamond heist, dubbed the "heist of the century", was the largest ever diamond heist and one of the largest robberies in history. Thieves stole loose diamonds, gold, silver and other types of jewelry valued at more than $100 million. It took place in Antwerp, Belgium, during the weekend of 15–16 February 2003. Though arrests were made and time was served, most of the diamonds stolen remain unrecovered.