A voiceless velar fricative is a type of consonantal sound used in some spoken languages. It was part of the consonant inventory of Old English and can still be found in some dialects of English, most notably in Scottish English, e.g. in loch, broch or saugh (willow).

The symbol in the International Phonetic Alphabet that represents this sound is ⟨x⟩, the Latin letter x. It is also used in broad transcription instead of the symbol ⟨χ⟩, the Greek chi, for the voiceless uvular fricative.

There is also a voiceless post-velar fricative (also called pre-uvular) in some languages, which can be transcribed as ⟨x̠⟩ or ⟨χ̟⟩. For voiceless pre-velar fricative (also called post-palatal), see voiceless palatal fricative.

Features of a voiceless velar fricative:

A voiceless velar fricative and its labialized variety are postulated to have occurred in Proto-Germanic, the ancestor of the Germanic languages, as the reflex of the Proto-Indo-European voiceless palatal and velar stops and the labialized voiceless velar stop. Thus Proto-Indo-European *ḱr̥nom "horn" and *kʷód "what" became Proto-Germanic *hurnan and *hwat, where *h and *hw were likely [x] and [xʷ]. This sound change is part of Grimm's law.

In Modern Greek, a voiceless velar fricative originated from the Ancient Greek voiceless aspirated stop /kʰ/ in a sound change that lenited all Greek aspirated stops to fricatives.