Ŝ is used in ISO 9:1995 (standard of transliteration into Latin characters of Cyrillic characters) for letter Щ, and is used in the orthography of the Tsilhqotʼin language.
Ŝ is the twenty-third letter in Esperanto orthography. Although it is written as sx and sh respectively in the x-system and h-system workarounds, it is normally written as S with a circumflex: ŝ.