Cajun cuisine (French: cuisine cadienne [kɥi.zin ka.dʒɛn], Spanish: cocina cadiense) is a subset of Louisiana cooking developed by the Cajuns, itself a Louisianan development incorporating elements of Native American, West African, French, and Spanish cuisine.

Cajun cuisine is often referred to as a "rustic" cuisine, meaning that it is based on locally available ingredients and that preparation is simple. Cajuns historically cooked their dishes, gumbo for example, in one pot.

Crawfish, shrimp, and andouille sausage are staple meats used in a variety of dishes. The aromatic vegetables green bell pepper (piment doux), onion, and celery are called "the trinity" by chefs in Cajun and Louisiana Creole cuisines. Roughly diced and combined in cooking, the method is similar to the use of the mirepoix in traditional French cuisine which blends roughly diced carrot, onion, and celery. Additional characteristic aromatics for both the Creole and Cajun versions may include parsley, bay leaf, thyme, green onions, ground cayenne pepper, and ground black pepper. Cayenne and Louisiana-style hot sauce are the primary sources of spice in Cajun cuisine, which usually tends towards a milder, well-balanced heat, despite the national "Cajun hot" craze of the 1980s and 1990s.

The Acadians are an ethnic group descended from French colonists who settled in what is today Eastern Canada in the early 17th century. In the mid-18th century, thousands were deported by the British during the French and Indian War in what they termed le Grand Dérangement, and many of them resettled in southern Louisiana where they are known as Cajuns.

Due to the extreme change in climate from that of Acadia, Acadians were unable to cook their original dishes. Soon, their former culinary traditions were adapted and, in time, incorporated Native American and African American traditions—as exemplified in the classic Cajun dish gumbo, which takes its name from the word for its principal ingredient, okra, in the West African Bambara language. In Louisiana, the Acadian settlers replaced the whole-wheat bread they were accustomed to with cornbread, which by the beginning of the 19th century they were eating with cane syrup. Between 1790 and 1810 most Louisiana Acadians bought one to three enslaved black persons, many from the West Indies, from whom they learned the use of new ingredients, including okra. The ragu sauces that the Cajuns developed are very similar to sauces used in French West Africa, possibly introduced by enslaved cooks.

Many other meals developed along these lines, adapted in part from Haiti, to become what are now considered classic Cajun cuisine traditions (in contrast to the more modern concepts associated with Paul Prudhomme's style).

Up through the 20th century, the meals were basic, not elaborate. The public's false perception of "Cajun" cuisine was based on Prudhomme's style of Cajun cooking, which was spicy, flavorful, and not true to the classic form of the cuisine.

Cajun and Creole cuisine have mistakenly been considered the same, but the origins of Creole cooking are in New Orleans, and Cajun cooking arose 40 years after its establishment. Today, most restaurants serve dishes that consist of Cajun styles, which Prudhomme dubbed "Louisiana cooking". In Cajun home cooking, these individual styles are still kept separate. However, there are fewer people cooking the classic Cajun dishes that would have been eaten by the original settlers.