State Road 18 (SR 18) is a short state road in the U.S. state of Florida. It begins in Worthington Springs in southern Union County and travels eastward for 6.60 miles (10.62 km) into Bradford County until it becomes County Road 18 at Brooker. It also has county road extensions, one of which is between Fort White and Worthington Springs, and the other between Brooker and SR 100 north of .