State Road 540 (SR 540) is a west–east route in Central Florida, serving Polk County.

It runs 19.2 miles (30.9 km) from the south side of the city of Lakeland to U.S. Route 27 (US 27).

It is a major route along the south side of Winter Haven, where it is known as Cypress Gardens Boulevard, and an important link between Winter Haven and Lakeland, the Polk Parkway, and subsequently Interstate 4 (I-4) and the Tampa Bay area.

SR 540 continues from the former site of Cypress Gardens to its eastern terminus at US 27 between the cities of Dundee and Lake Wales.

It begins at U.S. 17 in Eloise just south of Winter Haven where it is cosigned[citation needed] with County Road 655 (Snively Avenue).