Isak Larsson Flatabø (11 September 1896 – 22 January 1969) was a Norwegian politician for the Labour Party.
He was elected to the Norwegian Parliament from Hordaland in 1945, and was re-elected on four occasions.
On the local level, Flatabø was a member of Kvam municipality council from 1927 to 1940.
He was active in the International Organisation of Good Templars.
This article about a Norwegian politician born in the 1890s is a stub.