Flodday () is an uninhabited island, south-west of Barra in the Outer Hebrides of Scotland.
The island is one of the Barra Isles, lying west of Sandray. It consists of three parts, with a natural rock arch between the larger two. Facing west there are black cliffs.
The island has a small grey seal colony and is home to a subspecies of the dark green fritillary butterfly (Argynnis aglaja scotica).