Traditional Chinese characters are a standard set of Chinese character forms used to write Chinese languages. In Taiwan, the set of traditional characters is regulated by the Ministry of Education and standardized in the Standard Form of National Characters. These forms were predominant in written Chinese until the middle of the 20th century, when various countries that use Chinese characters began standardizing simplified sets of characters, often with characters that existed before as well-known variants of the predominant forms.

Simplified characters as codified by the People's Republic of China are predominantly used in mainland China, Malaysia, and Singapore. "Traditional" as such is a retronym applied to non-simplified character sets in the wake of widespread use of simplified characters. Traditional characters are commonly used in Taiwan, Hong Kong, and Macau, as well as in most overseas Chinese communities outside of Southeast Asia. As for non-Chinese languages written using Chinese characters, Japanese kanji include many simplified characters known as shinjitai standardized after World War II, sometimes distinct from their simplified Chinese counterparts. Korean hanja, still used to a certain extent in South Korea, remain virtually identical to traditional characters, with variations between the two forms largely stylistic.

There has historically been a debate on traditional and simplified Chinese characters. Because the simplifications are fairly systematic, it is possible to convert computer-encoded characters between the two sets, with the main issue being ambiguities in simplified representations resulting from the merging of previously distinct character forms. Many Chinese online newspapers allow users to switch between these character sets.

Traditional characters are known by different names throughout the Chinese-speaking world. The government of Taiwan officially refers to traditional Chinese characters as 正體字; 正体字; zhèngtǐzì; 'orthodox characters'. This term is also used outside Taiwan to distinguish standard characters, including both simplified, and traditional, from other variants and idiomatic characters. Users of traditional characters elsewhere, as well as those using simplified characters, call traditional characters 繁體字; 繁体字; fántǐzì; 'complex characters', 老字; lǎozì; 'old characters', or 全體字; 全体字; quántǐzì; 'full characters' to distinguish them from simplified characters.

Some argue that since traditional characters are often the original standard forms, they should not be called "complex". Conversely, there is a common objection to the description of traditional characters as "standard", due to their not being used by a large population of Chinese speakers. Additionally, as the process of Chinese character creation often made many characters more elaborate over time, there is sometimes a hesitation to characterize them as "traditional".

Some people refer to traditional characters as "proper characters" (正字; zhèngzì or 正寫; zhèngxiě) and to simplified characters as 簡筆字; 简笔字; jiǎnbǐzì; 'simplified-stroke characters' or 減筆字; 减笔字; jiǎnbǐzì; 'reduced-stroke characters', as the words for simplified and reduced are homophonous in Standard Chinese, both pronounced as jiǎn.

The modern shapes of traditional Chinese characters first appeared with the emergence of the clerical script during the Han dynasty c. 200 BCE, with the sets of forms and norms more or less stable since the Southern and Northern dynasties period c. the 5th century.

Although the majority of Chinese text in mainland China are simplified characters, there is no legislation prohibiting the use of traditional Chinese characters, and often traditional Chinese characters remain in use for stylistic and commercial purposes, such as in shopfront displays and advertising. Traditional Chinese characters remain ubiquitous on buildings that predate the promulgation of the current simplification scheme, such as former government buildings, religious buildings, educational institutions, and historical monuments. Traditional Chinese characters continue to be used for ceremonial, cultural, scholarly/academic research, and artistic/decorative purposes.