Kha, Khe, Xe or Ha (Х х; italics: Х х or Х х; italics: Х х) is a letter of the Cyrillic script. It looks the same as the Latin letter X (X x X x), in both uppercase and lowercase, both roman and italic forms, and was derived from the Greek letter Chi, which also bears a resemblance to both the Latin X and Kha.

It commonly represents the voiceless velar fricative /x/, similar to how some Scottish speakers pronounce the ⟨ch⟩ in “loch”, but has different pronunciations in different languages.

Kha is romanised as ⟨kh⟩ for Russian, Ukrainian, Mongolian, and Tajik, and as ⟨ch⟩ for Belarusian and Polish, while being romanised as ⟨h⟩ for Serbo-Croatian, Bulgarian, Macedonian, and Kazakh. It is also romanised as ⟨j⟩ for Spanish.

The Cyrillic letter Kha was derived from the Greek letter Chi (Χ χ).

The name of Kha in the Early Cyrillic alphabet was хѣръ (xěrŭ).

In the Cyrillic numeral system, Kha has a value of 600.

Kha is the twenty-third letter of the Russian alphabet. It represents the voiceless velar fricative /x/ unless it is before a palatalizing vowel, when it represents /xʲ/.

Kha represents the voiceless uvular fricative /χ/ in Ossetian. The digraph ⟨хъ⟩ represents the voiceless uvular plosive /q/.