Târgu Trotuș (Hungarian: Tatros) is a commune in Bacău County, Western Moldavia, Romania. It is composed of three villages: Târgu Trotuș, Tuta (Diószeg), and Viișoara (Viszóra).

Historical population

Year	Pop.	±%
2002	5,354	—
2011	4,969	−7.2%
2021	5,330	+7.3%
Source: Census data

At the 2021 census, the commune had a population of 5,330, an increase from the 2011 census, when the population was 4,969. At the 2002 census, 99.9% of inhabitants were ethnic Romanians; 63.3% were Roman Catholic and 36.5% Romanian Orthodox.

• Jeremiah of Wallachia (1556–1625), Capuchin lay brother

• History of Târgu Trotuș from the Târgu Trotuș Townhall (in Romanian)