Tritonia striata is a species of dendronotid nudibranch from the western Mediterranean. It is a marine gastropod mollusc in the family Tritoniidae.
The body is relatively slender and rectangular in cross-section. The oral veil has six papillae and there are four to six gill clusters arranged along the edge of the mantle, sitting opposite similar gills on the other edge. Between the gills there is a distinct mantle ridge. The body is a tranlsucent white with three characteristic thin longitudinal black lines running down the mantle. The outer lines can be broken into a series of dashes.
Schmekel & Portmann (1982) report it feeding on the soft coral Paralcyonium elegans. It is a small species, seldom reaching more than 5 mm in length.