The Seminole Wars (also known as the Florida Wars) were a series of three military conflicts between the United States and the Seminoles that took place in Florida between about 1816 and 1858. The Seminoles are a Native American nation which coalesced in northern Florida during the early 1700s, when the territory was still a Spanish colonial possession. Tensions grew between the Seminoles and American settlers in the newly independent United States in the early 1800s, mainly because enslaved people regularly fled from Georgia into Spanish Florida, prompting slaveowners to conduct slave raids across the border. A series of cross-border skirmishes escalated into the First Seminole War, when American general Andrew Jackson led an incursion into the territory over Spanish objections. Jackson's forces destroyed several Seminole, Mikasuki and Black Seminole towns, as well as captured Fort San Marcos and briefly occupied Pensacola before withdrawing in 1818. The U.S. and Spain soon negotiated the transfer of the territory with the Adams-Onis Treaty of 1819.

The United States gained possession of Florida in 1821 and coerced the Seminoles into leaving their lands in the Florida panhandle for a large Indian reservation in the center of the peninsula per the Treaty of Moultrie Creek. In 1832 by the Treaty of Payne's Landing, however, the federal government under United States President Andrew Jackson demanded that they leave Florida altogether and relocate to Indian Territory (modern day Oklahoma) as per the Indian Removal Act of 1830. Those who refused to move resisted violently, leading to the Second Seminole War (1835–1842), which was by far the longest and most wide-ranging of the three conflicts. Initially, less than 2,000 Seminole warriors employed hit-and-run guerilla warfare tactics and knowledge of the land to evade and frustrate a combined U.S. Army and Marine force that grew to over 30,000. Instead of continuing to pursue these small bands, American commanders eventually changed their strategy and focused on seeking out and destroying hidden Seminole villages and crops, putting increasing pressure on resisters to surrender or starve with their families.

By 1842, 3,612 Seminoles had relocated to the Indian Territory. A minority of about 350 to 500 remained in Florida, where they were allowed to remain in an uneasy truce. Tensions over new settlement in the state under the Armed Occupation Act of 1842 south of Tampa led to renewed hostilities, and the Third Seminole War broke out in 1855. By the cessation of active fighting in 1858, the few remaining bands of Seminoles in Florida had fled deep into the Everglades to land unwanted by American settlers.

Taken together, the Seminole Wars were the longest, most expensive, and most deadly of all American Indian Wars.

Spanish Florida was established in the 1500s, when Spain laid claim to land explored by several expeditions across the future southeastern United States. The introduction of diseases to the indigenous peoples of Florida caused a steep decline in the original native population over the following century, and most of the remaining Apalachee and Tequesta peoples settled in a series of missions spread out across north Florida. Spain never established real control over its vast claim outside of the immediate vicinity of its scattered missions and the towns of St. Augustine and Pensacola, however, and English settlers established several colonies along the Atlantic coast during the 1600s. After the establishment of the English Province of Carolina in the late 17th century, a series of raids by Carolina settlers and their Indian allies into Spanish Florida devastated both the mission system and the remaining native population.

English settlers repeatedly came into conflict with Native Americans as they expanded further westward, resulting in a stream of refugees relocating to depopulated areas of Florida. A majority of these refugees were Muscogee (Creek) Indians from Georgia and Alabama, and during the 1700s, they came together with other native peoples to establish independent chiefdoms and villages across the Florida panhandle as they coalesced into a new culture which became known as the Seminoles.

Beginning in the 1730s, Spain established a policy of providing refuge to runaway slaves from the British Southern Colonies. Hundreds of Black people escaped slavery to Florida over the ensuing decades, with most settling near St. Augustine at Fort Mose and a few living amongst the Seminole, who treated them with varying levels of equality. Their numbers increased during and after the American War of Independence, and it became common to find settlements of Black Seminoles either near Seminole towns or living independently, such as at Negro Fort on the Apalachicola River. The presence of a nearby refuge for free Africans was considered a threat to the institution of chattel slavery in the southern United States, and settlers in the border states of Mississippi and Georgia in particular accused the Seminoles of inciting slaves to escape and then stealing their human property. In retaliation, plantation owners organized repeated raids into Spanish Florida in which they captured Africans they accused of being escaped slaves and harassed the Seminole villages near the border, resulting in bands of Seminoles crossing into U.S. territory to stage reprisal attacks.

The increasing border tensions came to a head on 26 December 1817, as the U.S. War Department wrote an order directing General Andrew Jackson to take command in person and bring the Seminoles under control, precipitating the First Seminole War. The war preceded with the destruction of the Negro Fort in July 1816, and subsequently Jackson's forces destroyed several Seminole/Creek and Miccosukee settlements including Fowltown pursuing them and Black Seminoles and allied Maroons across northern Florida in 1818. Jackson's expedition culminated in April 1818 with the Arbuthnot and Ambrister incident. The Spanish government expressed outrage over Jackson's "punitive expeditions" into their territory and his brief occupation of Pensacola the capital of their colony of West Florida. But as was made clear by several local uprisings and other forms of "border anarchy", Spain was no longer able to defend nor control Florida and eventually agreed to cede it to the United States per the Adams–Onís Treaty of 1819, with the transfer taking place in 1821. According to the terms of the Treaty of Moultrie Creek (1823) between the United States and Seminole Nation, the Seminoles were removed from Northern Florida to a reservation in the center of the Florida peninsula, and the United States constructed a series of forts and trading posts along the Gulf and Atlantic Coasts to enforce the treaty.