State Route 5 (abbreviated SR 5) is a major south–north highway in West Tennessee. SR 5 is 120 miles (190 km) long and, except for the section north of Union City, is overlapped with US 45 & 45W.

SR 5 is the hidden designation for US 45 and US 45W for most of the highway's length through the state. SR 5 at its southern terminus is a 4-lane, divided, limited-access expressway and is designated as a primary state highway. In contrast, the northern terminus is quite rural in nature and exists as a two-lane secondary state highway. SR 5 follows Highland Avenue through the City of Jackson, Tennessee and US 45 Business through Humboldt, Tennessee. At Union City, Tennessee, SR 5 becomes a fully signed secondary highway and follows First Street and Main Street through the city. At its junction with US 51, SR 5 continues along Main Street and becomes a primary state highway which overlaps Tennessee State Route 22. At Lake Drive in Union City, Tennessee State Route 22 turns west toward Samburg, Tennessee. SR 5 past Lake Drive is signed as a secondary state highway and continues north toward the state line. The signed portion of SR 5 exists entirely within Obion County, Tennessee and is approximately 7.8 miles (12.6 km) in length.

SR 5 traverses the following counties (south to north) shown in the table below.

Several old alignments (most are two-lane) of SR 5 exist throughout the state with the most notable examples being near the Mississippi state line, a section of old highway 45 between Bethel Springs and Selmer, Tennessee State Route 367 through Trenton, and a long stretch of old highway between Trenton and Rutherford.

Originally, SR 5 north of Trenton followed a much different route from the current alignment. From Trenton, SR 5 bent to the northeast, following the old Dresden Road as far as Greenfield, where it turned north and roughly followed the present-day SR 43. As evidenced by road maps published by the National Map Company and Rand McNally, sometime between 1927 and 1935, SR 5 was rerouted to follow the former SR 41 north to Kenton and on to Union City.

TDOT has proposed widening SR 5 in Obion County as part of The 2008-2010 Transportation Improvement Program. Right-of-way acquisition will begin in FY 2008 on a section of SR 5 from Troy Station Road to Allie Campbell Road and in FY 2010 for the section between Allie Campbell Road and SR 22. This will leave a two-lane section of SR 5 from Rutherford, Tennessee to a point just north of the Obion River.