Jarlsberg (pronounced /ˈjɑrlzbərɡ/) is a mild cow's-milk cheese with large irregular holes or what are commonly referred to as "eyes", originating from Jarlsberg, Norway.

Jarlsberg has a yellow-wax rind and a semi-firm yellow interior. The flavor is mild, buttery, nutty and slightly sweet. It is an all-purpose cheese, good both for cooking and for eating as a snack. It has a characteristic smooth, shiny-yellow body, and a creamy supple texture. Jarlsberg Special Reserve is produced in Norway in limited quantities. It is aged a minimum of one year and is distinguished by medium to large holes.

The history of this cheese can be traced back to the middle 1850s. Anders Larsen Bakke (1815–1899), was a farmer and entrepreneur and a pioneer in Norway's dairy industry. He produced cheese in the Våle village in what was then the county of Jarlsberg and Larviks Amt (now Vestfold), 80 km south of Oslo. The cheese shares similarities with Emmenthal, introduced to Vestfold by Swiss cheese makers during the 1830s. The cheese (and Bakke's accomplishments) was first noted in the annual county report of Jarlsberg and Larviks Amt 1855.

The Jarlsberg cheese that we know today is a result of a long period of research and development which was carried out by researchers at the Dairy Institute at the Agricultural University of Norway. The cheese making process was developed by Ola Martin Ystgaard, professor of the Agricultural University of Norway. Starting in 1956, Ystgaard and some of his students eventually came up with the recipe that is used today. Commercial production of cheese began in the 1960s.

The largest producer of Jarlsberg today is the TINE BA factory in Elnesvågen in western Norway. TINE is one of the twelve agricultural cooperatives in Norway and the largest Norwegian dairy product cooperative. The corporation domestically offers the entire spectrum of dairy products. In addition to Jarlsberg, TINE's internationally known products include Snøfrisk goat cheese, Ridder cheese, and Ski-Queen (geitost). Jarlsberg accounts for 60% of TINE's total export.

Jarlsberg is also produced in the United States on license at Alpine Cheese in Ohio, and by Dairygold in Ireland. In the United States alone it is sold in over 30,000 supermarkets and a ton of the cheese is eaten per hour.