Ya, Ia or Ja is a letter of the Cyrillic script, the civil script variant of Old Cyrillic Little Yus, and possibly Iotated A. Among modern Slavic languages, it is used in the East Slavic languages and Bulgarian. It is also used in the Cyrillic alphabets used by Mongolian and many Uralic, Caucasian and Turkic languages of the former Soviet Union.

The Cyrillic script, Slavonic script or simply Slavic script is a writing system used for various languages across Eurasia. It is the designated national script in various Slavic, Turkic, Mongolic, Uralic, Caucasian and Iranic-speaking countries in Southeastern Europe, Eastern Europe, the Caucasus, Central Asia, North Asia, and East Asia, and used by many other minority languages.