The Hyrcanian Forest is a green belt in the north of Iran, and one of its distinctive features is the presence of an extraordinary variety of moss species. The Brachytheciaceae is distributed worldwide and comprises 62 genera and almost 570 species. Sciuro-hypnum curtum is one of the most variable species of the Brachytheciaceae and is here reported for the first time for the moss flora of Iran. The specimen was collected from northern Iran in the autumn of 2018 at an altitude of 581m in the southeast of Rezvanshahr city in Guilan Province. Here we provide description, illustrations, geographic distribution, and the locality and habitat of the new record.