Penfolds is Australia's most famous wine producer, best known for its flagship wine Grange, one of the most acclaimed wines in the world. Among many other accolades, the 1955 Grange was named one of the top 12 wines of the 20th Century by Wine Spectator Magazine; the 1971 vintage was ranked as the greatest wine of the 1970s by FINE Wine Magazines and tastingbook.com, and the 2008 gained a perfect 100-point score from both Wine Spectator and Robert Parker's Wine Advocate. It is a mainstay of the secondary market – auction prices for the wine have regularly been used as key performance indicators for the wider Australian economy.

Occasionally Grange is 100-percent Shiraz – the 2011 was the sixth time that happened in six decades – but more typically it also contains up to around 15 percent Cabernet Sauvignon. It is the flagship for Penfolds' celebrated multi-vineyard, multi-region blending philosophy, and is sourced from Barossa, McLaren Vale, Coonawarra (occasionally) and Magill Estate at the base of the Adelaide Hills, just to the east of the city. 

Penfolds has a long-standing reputation for consistent high quality across its broad portfolio, and there are several other wines that feature regularly in auctions, including the Bin 707 Cabernet Sauvignon, St. Henri and RWT Shiraz wines, Bin 389 Cabernet – Shiraz and Bin 407 Cabernet Sauvignon. These have been joined by experimental or periodic releases such as the Block 42 Cabernet Sauvignon and Bin 60a Cabernet – Shiraz. A desire to introduce a flagship white led to the 1995 debut of the Yattarna Chardonnay. The extensive portfolio includes numerous other bin-numbered releases, the Max's, Koonunga Hill and Cellar Reserve ranges, and a selection of tawny fortified wines.

The company has extensive vineyard holdings primarily located across the various winegrowing regions of South Australia. Some of these are among the most iconic properties in the country, including Magill Estate, and the Kalimna and Koonunga Hill vineyards in the northern Barossa. In addition, a wide range of grape growers are also used, both in the core South Australian regions and further afield, particularly for Chardonnay. In total, around 220 different sources contribute to production.

Penfolds was founded in 1844 when Dr Christopher Rawson Penfold and his family arrived in Australia from England. He paid ₤1200 for 500 acres (200 hectares) of prime land in what was then called Mackgill, and planted it with cuttings sourced from France, with the intention of making medicinal wine. By the 1920s, the company accounted for half of all wine sales across the country. Penfolds and its parent company Southcorp have had a complex history in recent decades. Since 2011 the company has been part of Treasury Wine Estates.