Hippeutis complanatus, or the flat ram's-horn snail, is a species of small air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk or micromollusk in the family Planorbidae, the ram's horn snails.

The species is found in the Palearctic zone, including Europe.

This minute shell is almost perfectly planispiral and shaped like a lens.

The shell color varies from offwhite to a brownish yellow.

This snail lives in ponds and ditches, and prefers calcium-rich waters.