The Naugatuck River Valley is a region of the state of Connecticut located in the central-southwest of the state, and is focused around the southern reaches of the Naugatuck and Housatonic Rivers. It is also known within the state as simply the Valley or the Greater Valley. The Naugatuck River Valley is comprised of the towns of Ansonia, Beacon Falls, Derby, Naugatuck, Oxford, Seymour, and Shelton.

The Valley is a unique region straddling Fairfield and New Haven counties, and was once the most prosperous part of Connecticut in the early days of industrialization. The region was home to key factories in national industries, most notably rubber manufacturing, petrochemical production, and shipbuilding. The friction match was invented in the town of Beacon Falls, and Naugatuck was the birthplace of Naugahyde. This industrial past has given the region a heavily urban landscape, with many factory buildings rising prominently along the riverside and dominating the central districts of the towns.

After the Great Depression, however, the area's manufacturing base suffered a prolonged period of deindustrialization, leaving behind weak economies and empty buildings typical of Rustbelt landscapes. In 1955, the area's fortunes were further reversed when floodwaters brought by hurricane rains devastated the region. High unemployment, poverty, and isolation has since marked the Valley, which continues to stand as a rust-belt between the commuter towns of Fairfield county and the quiet suburbs of Greater New Haven; this isolation and economic stagnancy, however, has preserved many working-class features within the area that may have otherwise been erased with suburbanization as has happened in much of New England. In contrast with other regions of Connecticut, for example, the Valley maintains a high emotional and cultural involvement with its high school football teams and rivalries.

In 2000, as a sign of its continued perserverence, the seven city region was selected as an "All-American City" -- to note its award as a whole, the award title was specially changed to "All-American Valley."