Icewine (or ice wine; German: Eiswein) is a type of dessert wine produced from grapes that have been frozen while still on the vine. The sugars and other dissolved solids do not freeze, but the water does, allowing for a more concentrated grape juice to develop. The grapes' must is then pressed from the frozen grapes, resulting in a smaller amount of more concentrated, very sweet juice. With icewines, the freezing happens before the fermentation, not afterwards. Unlike the grapes from which other dessert wines are made, such as Sauternes, Tokaji, or Trockenbeerenauslese, icewine grapes should not be affected by Botrytis cinerea or noble rot, at least not to any great degree. Only healthy grapes keep in good shape until the opportunity arises for an icewine harvest, which in extreme cases can occur after the New Year, on a northern hemisphere calendar. This gives icewine its characteristic refreshing sweetness balanced by high acidity. When the grapes are free of Botrytis, they are said to come in "clean". This results in a very complex and sweet wine. Much icewine is made from the grapes Riesling, Vidal, Cabernet Franc and Cabernet Sauvignon, but there is also icewine made from Shiraz, Merlot, Sangiovese and others.

Icewine production is risky (the frost may not come at all before the grapes rot or are otherwise lost) and requires the availability of a large enough labour force to pick the whole crop within a few hours, at a moment's notice, on the first morning that is cold enough. The grapes for icewine must only be harvested when they are frozen naturally and the temperature must be -8 C (20°F) or below when they are picked. This results in relatively small amounts of ice wine being made worldwide, making icewines generally expensive.

Icewine production is limited to that minority of the world's wine-growing regions where the necessary cold temperatures can be expected to be reached with some regularity. Canada is the world's largest producer of icewine, producing a greater volume of icewine than all other countries combined with Ontario producing over 90% of Canada's icewine, followed by Germany^{[citation needed]}.

There are indications that frozen grapes were used to make wine in Roman times. Pliny the Elder (AD 23 – 79) wrote that certain grape varieties were not harvested before the first frost had occurred. The poet Martial recommended that grapes should be left on the vine until November or until they were stiff with frost. Details as to the winemaking and description of these wines are unknown. It cannot be completely ruled out that the descriptions refer to dried grape wines, a common style of wine in Roman times, where the raisin-like grapes were harvested late enough for the first frost to have fallen. In either case, the method seems later to have been forgotten. Wine from Chiomonte in the Val di Susa was popular in Roman times and this town still today produces one of Italy's few ice wines.

It is believed that the first post-Roman icewine was made in Franconia in 1794. Better documentation exists for an ice-wine harvest in Dromersheim close to Bingen in Rheinhessen on February 11, 1830. The grapes were of the 1829 vintage. That winter was harsh and some wine growers had the idea to leave grapes hanging on the vine for use as animal fodder. When it was noticed that these grapes yielded very sweet must, they were pressed and an icewine was produced. Sweet wines produced from late harvested grapes were well-established as the most valued German wine style by the early 19th century, following the discovery of Spätlese at Schloss Johannisberg in Rheingau in 1775, and the subsequent introduction of the Auslese designation. These wines would usually be produced from grapes affected by noble rot. Thus, eiswein is a more recent German wine style than the botrytised wines.

Throughout the 19th century and until 1960, eiswein harvests were a rare occurrence in Germany. Only six 19th-century vintages with eiswein harvests have been documented, including 1858, the first eiswein at Schloss Johannisberg. There was little effort to systematically produce these wines during this period, and their production was probably the rare result of freak weather conditions. It was the invention of the pneumatic bladder press which made the production of ice wine practical and led to a substantial increase in the frequency and quantity of production.

Production of a number of German icewines began to increase in 1961, and the wine increased in popularity in the following years. The production has been assisted by other technological inventions in the form of electric lighting driven by portable generators (to assist harvest in the cold hours of early-morning darkness, before sunrise and the grapes thaw), and remotely-controlled temperature alarms. After re-thawing, the grapes will spoil quickly since ice crystals destroy cell walls. Thus, the harvest must be completed within a few hours on the first morning that is cold enough. Plastic films are used for "packaging" the vines during the waiting period between ripeness and first frost to protect the ripe grapes from being eaten by wildlife.

Icewine was first produced in the Okanagan Valley of British Columbia by German immigrant Walter Hainle in 1972. This icewine was the result of an early and unexpected frost, and yielded 40 litres (8.8 imp gal; 11 US gal) of wine, which Hainle originally did not intend to sell, although he did so in 1978.