Chinese characters (traditional Chinese and Japanese: 漢字; simplified Chinese: 汉字; pinyin: hànzì ; Cantonese Jyutping: hon3 zi6 ; Wade–Giles: han4 tzŭ4 ; rōmaji: kanji ; "Han characters") are logograms used to write the Chinese languages and several other languages historically influenced by Chinese culture. Chinese characters are the oldest continuously used writing system in the world, with a documented history spanning than three millennia. Over this span, the function and style of characters has evolved greatly. Most recently, countries using Chinese characters have standardised their forms and pronunciations. Broadly, simplified characters are used in mainland China, Singapore, and Malaysia, while traditional characters are used in Taiwan, Hong Kong, and Macau.

Chinese characters were historically adapted to write other languages spoken within the Sinosphere. Chinese characters in Japanese, Korean, and Vietnamese are known as kanji, hanja, and chữ Hán respectively. Of these, each also created their own characters for their internal use. These languages generally function very differently from Chinese, and belong to their own independent language families. In part due to this difference, Korean and Vietnamese are now written almost exclusively with alphabets designed to replace Chinese characters. This leaves Japanese as the sole major language unrelated to Chinese still written with Chinese characters.

Unlike in phonetic writing systems, where individual letters roughly correspond to phonemes, the Chinese writing system associates each logogram with a syllable. In fact, written characters, syllables, and morphemes—the basic units of meaning in a language—largely correspond one-to-one with one another in Chinese languages. However, written Chinese is not ideographic—characters fundamentally correspond to spoken syllables, not to the abstracted ideas themselves.

To a higher degree than most major languages, modern spoken Chinese has many homophones: the same spoken syllable can be represented by one of several different characters depending on context. Additionally, a particular character may have a range of different meanings; different readings of the same character may have different pronunciations and even etymologies. In Standard Chinese, one-fifth of the 2,400 most common characters have several pronunciations.