The Mimosa is a cocktail that combines equal parts of chilled sparkling wine (typically Champagne) and citrus juice, most commonly orange juice. The drink is served in a champagne flute and is usually consumed as part of brunch or celebratory events.

The Mimosa originated in France. It is widely believed to have been created around 1925 at the Hôtel Ritz in Paris by bartender Frank Meier. The drink is named after the yellow-flowered mimosa plant (Acacia dealbata) due to its similar color. The Mimosa closely resembles the Buck’s Fizz, a cocktail that was created earlier, in 1921, at the Buck's Club in London; however, the Buck’s Fizz uses more sparkling wine relative to orange juice.

There is debate regarding whether the Mimosa is a distinct drink or simply a variation of Buck’s Fizz. In practice, the ratio of Champagne to orange juice may vary, but the standard definition is an equal split.

Classic recipe guidelines do not call for additional ingredients, though some variants include Grand Marnier, triple sec, or other liqueurs. The Mimosa is served well-chilled, and occasionally garnished with orange slices or twists.

The Mimosa has become associated with brunch culture, especially in English-speaking countries, and is often offered in free-flow or bottomless brunch packages at restaurants.

In terms of official recognition, the International Bartenders Association (IBA) lists the Mimosa as an official cocktail. The IBA recipe specifies equal measures of Champagne and orange juice.

Though the Mimosa was initially most popular in France and England, it has become common worldwide. The drink’s low alcohol content and light flavor make it a frequent choice for morning or daytime consumption. There are several variations that use different juices, such as grapefruit (to make a “Megmosa”) or cranberry (to make a “Poinsettia”).