Florida's 3rd congressional district is an electoral district of the United States House of Representatives located in Florida. It presently comprises a large section of north central Florida, including the entire counties of Alachua, Baker, Bradford, Columbia, Dixie Gilchrist, Hamilton, Levy, Suwannee, and Union, along with the majority of Lafayette and Marion County. The city of Gainesville is in the district as well as part of Ocala (its northern suburbs).

Redistricting in Florida, effective for the 2012 federal elections, radically altered the nature of the 3rd district. From 1993 through 2012 the district called the 3rd district comprised an entirely different territory, roughly similar to the 5th district as of 2013^[update]. Likewise the present territory of the new 3rd district, as of the 2012 elections, is made up of parts of the former 2nd, 4th, 5th, and 6th districts, though it is geographically similar to the pre-2013 6th district. The former 3rd district was an intentionally gerrymandered territory designed to unite disparate areas of northeastern Florida with significant African-American populations into a black-majority district, and was overwhelmingly Democratic in voting patterns.

The new 3rd district has a majority white population, largely in rural areas and small towns. The only cities of any size in the district are Gainesville and Ocala. The district has been represented by Republican Kat Cammack since 2021.

While Florida has had at least three congressional districts since the 1900 U.S. census, the 1993–2012 3rd congressional district dates to reapportionment done by the Florida Legislature after the 1990 U.S. census. Because Florida has a large population of African Americans, but not a large enough concentration anywhere in the state to easily configure a congressional district with a majority, there were several attempts to create a few gerrymandered districts which were certain to elect an African American candidate. This created an odd coalition of black Democrats and Republicans who supported such districts (since this not only created black-majority districts, but also made "safer" Republican districts elsewhere). This effort was opposed by many white Democrats, but eventually, this idea won the support of the state legislature and this district was created as a result.^[5]

The 1993–2012 3rd congressional district was geographically diverse. Starting from the southern part of the district, it included the Pine Hills area of the Orlando-Kissimmee Metropolitan Area with small pockets of African-American neighborhoods in the cities of Sanford, Gainesville, Palatka, and finally the larger African American communities of Jacksonville. Connecting these areas were regions that are sparsely populated—either expansive rural areas or narrow strips which are only a few miles wide. Barack Obama received 73% of the vote in this district in the 2008 Presidential election. The old 3rd district was represented from 1993 through 2012 by Corrine Brown, who was elected to the similar new 5th district in the November 2012 elections.

• 2003–2013
• 2013–2017
• 2017–2023