Antti Isotalo, also known as Isoo-Antti, Isoon talo(o)n Antti or Isontalon Antti (born 30 August 1831 in Hanhimäki, Alahärmä - died 8 August 1911 in Alahärmä) was a Finnish farmer and puukkojunkkari, who led the criminal gang Isoo-joukko (literally, 'Iso[talo]'s Bunch') together with Antti Rannanjärvi from 1856 to 1867.
Isotalo was a restless character, and his hobbies included horse racing. He was a shrewd businessman, and felt right at home at the town market. He seldom had to gather people around himself, instead people were reported to gather around him on their own initiative. He was a fearless and ruthless fighter. Because of his large size, he was often asked to act as a security guard in festivities.
Isotalo was accused of homicide in 1858, but was released due to lack of conclusive evidence. Based on new witness statements, the court sentenced him to death in 1869. The Senate of Finland changed the sentence to 12 years of hard labour at the Hämeenlinna correctional facility. Isotalo is reported to have denied his guilt for the rest of his life. In prison he behaved well. Isotalo was married three times.