The Sandettie Bank (French: Banc de Sandettié) is an elongated sandbank in the southern North Sea, more specifically about in the middle of the northeastern entrance to the Strait of Dover.
North-west of it are the hazardous Goodwin Sands, south of it the sandbank Ruytingen.
The shoal represents a significant threat to the major shipping lanes in the Strait of Dover.
From 1902 to 1989 it was marked by a succession of French lightships, all bearing the name Sandettié while deployed there.
In the northwest part of the area erosion cut a basin in the Tertiary strata.