AbstractThe red algaTiffaniella gorgonea(Wrangeliaceae, Rhodophyta) is found and described for the first time from the Mediterranean Sea. This species was collected growing as epiphyte on three species ofCodiumin the lower intertidal zone from Dalya, Cabo Negro and Al-Hoceima on the Mediterranean coast of Morocco. Moroccan specimens were studied in detail and compared with two other closely related species reported previously from Morocco and the Mediterranean Sea. A key to the Mediterranean and Moroccan species ofTiffaniellais provided. Habitat, geographical distribution, and the possible vector of introduction of the new alien are presented and discussed in this work. Taxonomic remarks, a description and images of the macroscopic and microscopic characters are provided for this taxon.