Hansen Bayou, covering 16 acres, is a bay situated in Sarasota County.

Connecting Roberts Bay and Sarasota Bay, Hansen Bayou is used almost exclusively by the residents along its shores at the north end of Siesta Key. When it was built on "Hansen's Bayou" in 1912, the Bay Island Hotel was a major attraction in the community. This waterbody is included in the Sarasota Bay Estuary Program and is a SWFWMD SWIM waterbody.