Ahnfeltia plicata, the landlady's wig, is a species of red alga in the family Ahnfeltiaceae.

The landlady's wig forms tufted perennial plants with wiry fronds, branching from a discoid holdfast.

[1] The landlady's wig could be confused with Cordylecladia erecta but that species is less common and is thicker with more rigid, regularly branched fronds.

[4] The landlady's wig is found on either side of the north Atlantic Ocean [4] from the middle shore down to depths of about 12 metres (39 ft).

On male plants there are spermatangial sori that form swellings on the middle parts of the frond.