Smyrna is a town in Rutherford County, Tennessee. Smyrna's population was 53,070 at the 2020 census, making it the largest town in Tennessee by population in that census. In 2007, U.S. News & World Report listed Smyrna as one of the best places in the United States to retire. Smyrna is part of the Nashville metropolitan statistical area.

The town of Smyrna has its European American roots in the early 19th century and began as an agrarian community. It was important during the Civil War because its railroad station lies between Nashville and Chattanooga. One of the major events of the war for the town involved the Confederate States soldier Sam Davis, who, after being charged with spying, gave up his life instead of giving any information to the Union Army. He was captured November 20, 1863, and was hanged by Union forces on November 27 of that year. The Sam Davis Plantation, located on 160 acres (0.65 km2) of well-maintained farmland, is the town's most important historical site.

Smyrna was originally incorporated in 1869 but its charter was rescinded by the state several years later. In 1915, the town re-incorporated and adopted a commission-mayor form of government.

In 1941 during World War II, Sewart Air Force Base was established here and served as a B-17 Flying Fortress and B-24 advanced training facility. During the 1950s and 1960s, the military personnel and dependents totaled more than 10,000 persons stationed at the base. The base was scheduled for closing in 1971. Most of the property was divided among the State of Tennessee, Rutherford County, and the Metropolitan Nashville Airport Authority. On its portion, the state opened and operates a Tennessee Army National Guard base and the Tennessee Rehabilitation Center. Much of the additional land was developed as the Smyrna/Rutherford County Airport Authority in 1990.

During the 1970s, many new industries moved to the area. The city began a period of growth stimulated by production of such companies as Better Built Aluminum, Cumberland Swan (currently known as Vi-Jon, Inc.), and Square D building plants. In the early 1980s, Nissan Motors constructed a manufacturing plant in the city, and in 1983, the first vehicle was produced. The Nissan plant now employs around 8,400 workers, has a production capacity of 640,000 vehicles annually, and covers an area of 5,200,000 sq ft (480,000 m2). In 2012, Smyrna began manufacturing Nissan's electric car, the Nissan Leaf, and its batteries.

On March 14, 2000, the mayor and board of commissioners adopted a new charter. The city now operates under the city manager form of government, whereby the commissioners hire a city manager for daily operations.

On June 2, 2016 Blue Angels #6 crashed in Smyrna when practicing for the Great Tennessee Air show, killing pilot Capt. Jeff Kuss, USMC. The people of Smyrna raised funds to have a memorial built in his honor. The Capt. Jeff Kuss USMC Memorial sits across from the Smyrna Airport, where Capt. Kuss departed on his tragic final flight, and the centerpiece is a retired F/A-18 Hornet loaned to Smyrna from the United States Navy, painted in the colors of the Blue Angels performance squadron with Capt. Kuss' name under the cockpit hatch and the number 6 on the tails to represent which plane he flew on his final flight.

According to the United States Census Bureau, the town has a total area of 23.0 square miles (60 km2), of which 22.8 square miles (59 km2) is land and 0.1 square miles (0.26 km2) (0.61%) is water.

Portions of the Percy Priest Lake reservoir lies within the town limits. The two main waterways are Stones River and Stewarts Creek.

As of the 2020 United States census, there were 53,070 people, 18,059 households, and 12,282 families residing in the town.

As of the census of 2010, there were 39,974 people, 14,807 households, and 10,509 families living in the city. The population density was 1,753.25 persons per square mile, and the housing unit density was 649.43 units per square mile. The racial makeup of the city was 75.00% White, 11.21% Black or African American, 4.35% Asian, 0.59% Native American, 0.08% Pacific Islander, 6.02% from other races, and 2.75% from two or more races. Those of Hispanic or Latino origins constituted 10.72% of the population.

Of the 14,807 households, 37.23% had children under the age of 18 living in them, 50.46% were married couples living together, 5.54% had a male householder with no wife present, 14.98% had a female householder with no husband present, and 29.03% were non-families. 23.03% of all households were made up of individuals, and 5.94% had someone living alone who was 65 years of age or older. The average household size was 2.68 and the average family size was 3.15.

Of the 39,974 people living in the city, 27.89% were under the age of 18, 63.50% were between the ages of 18 and 64, and 8.60% were 65 years of age or older. The median age was 33.0 years. 51.32% of all persons were female and 48.68% were male.

The median household income in the city was $51,505, and the median family income was $61,286. Males had a median income of $43,633 versus $37,029 for females. The per capita income for the city was $24,448. About 9.4% of families and 12.2% of the population were below the poverty line, including 18.3% of those under the age of 18 and 7.4% of those age 65 and over.

As of the census of 2000, there were 25,569 people, 9,608 households, and 7,061 families living in the town. The population density was 1,119.8 inhabitants per square mile (432.4/km2). There were 10,016 housing units at an average density of 438.6 per square mile (169.3/km2). The racial makeup of the town was 87.23% White, 7.82% African American, 0.29% Native American, 1.21% Asian, 0.08% Pacific Islander, 1.81% from other races, and 1.56% from two or more races. Hispanic or Latino of any race were 4.31% of the population.

There were 9,608 households, out of which 39.8% had children under the age of 18 living with them, 55.0% were married couples living together, 14.2% had a female householder with no husband present, and 26.5% were non-families. 21.1% of all households were made up of individuals, and 4.3% had someone living alone who was 65 years of age or older. The average household size was 2.62 and the average family size was 3.04.

In the town, the population was spread out, with 27.6% under the age of 18, 10.5% from 18 to 24, 35.1% from 25 to 44, 19.9% from 45 to 64, and 6.8% who were 65 years of age or older. The median age was 32 years. For every 100 females, there were 95.9 males. For every 100 females age 18 and over, there were 92.9 males.

The median income for a household in the town was $44,405, and the median income for a family was $51,550. Males had a median income of $37,130 versus $27,325 for females. The per capita income for the town was $19,704. About 6.7% of families and 8.8% of the population were below the poverty line, including 11.4% of those under age 18 and 8.2% of those age 65 or over.

The Nissan Smyrna Assembly Plant is the largest automotive assembly plant in the US, making 640,000 cars per year. It began in 1983, and has made more than 10 million cars since then. Manufacturing of batteries for the Leaf began at the site in 2012. Nissan's goal is that the plant in Smyrna will eventually produce 150,000 electric cars, and 200,000 electric car batteries per year. In addition to serving as the U.S. production site for the Leaf, the plant assembles five other models.

The top employers in the city are:

Prior to their dissolution, RegionsAir (formerly Corporate Airlines) and Capitol Air were headquartered in Smyrna.

Smyrna has 10 parks, a public golf course, 7 miles of greenway trails and an outdoor water park.