(Top)口字頭 kǒuzìtǒu Radical 30 or radical mouth (口部) meaning 'mouth' is one of 31 of the 214 Kangxi radicals that are composed of 3 strokes.

In the Kangxi Dictionary, there are 1,146 characters (out of 40,000) to be found under this radical.

口 is also the 37th indexing component in the Table of Indexing Chinese Character Components predominantly adopted by Simplified Chinese dictionaries published in mainland China.

The radical is also used as an independent Chinese character.

It is one of the kyōiku kanji or kanji taught in elementary school in Japan.