Dominion Diamond Mines (formerly known as Dominion Diamond Corporation, Harry Winston, and Aber) is a Canadian specialist diamond mining company.

The company holds a 40% stake in the Diavik Diamond Mine Project. Production at the Diavik Diamond Mine, Canada's second diamond mine, is operated by Dominion Diamond Mines' joint venture partner, Diavik Diamond Mines Inc., a subsidiary of Rio Tinto Group. The mine began producing diamonds in November 2002.

In 2012 the company purchased all of BHP Billiton's diamond assets; the primary asset is the Ekati Diamond Mine, which is adjacent to the Diavik Mine.

Diavik and Ekati combined are estimated to produce over 7 million carats of diamonds in 2014, worth an estimated $1.1 billion. Diavik and Ekati are currently ranked the 9th and 19th largest diamond mines in the world, respectively, according to total carat production.

The company's participation in the retail segment of the diamond pipeline was by means of its ownership of Harry Winston, Inc., a chain of retail stores. On January 14, 2013 the company announced that it has entered into an agreement to sell its luxury brand diamond jewelry and timepiece division, Harry Winston Inc., to The Swatch Group Ltd. for US$750 million plus their assumption of up to US$250 million of pro forma net debt. The transaction included the brand and all the activities related to jewelry and watches, including the 535 employees worldwide and the production company in Geneva (Switzerland).

Aside from its corporate office in Calgary, Dominion Diamond Mines also has a rough diamond sorting facility in Toronto and a marketing office in Antwerp, Belgium. Harry Winston sells Tiffany & Co. about 25% of the diamonds in Winston's share and sells the remainder on the Antwerp open diamond market through its rough diamond dealer subsidiary, Aber International.

In March 2017, Dominion Diamond announced it had received an unsolicited and non-binding expression of interest from The Washington Companies to acquire the Company for US$1.1 billion.

In June 2017, a deal was signed with online diamond retailer James Allen to make it the exclusive online retailer of CanadaMark diamonds.