Little Yus (Ѧ, ѧ) and Big Yus (Ѫ, ѫ), or Jus, are the letters representing two Common Slavonic nasal vowels, in the early Cyrillic and Glagolitic alphabets. Each can occur in iotified form (Ѩ, ѩ, Ѭ, ѭ), as a ligature with the letter I.

Cyrillic Little Yus (left) and Big Yus (right); normal forms (above) and iotified (below)

Phonetically, Little Yus represents IPA [ɛ̃], and Big Yus IPA [ɔ̃].

Names of the letters do not imply capitalization: both Little and Big Yus exist in majuscule and minuscule variants.