Pinyin (Simplified Chinese: 汉语拼音; Traditional Chinese: 漢語拼音; Pinyin: Hànyǔ Pīnyīn), also known as scheme of the Chinese phonetic alphabet (Simplified Chinese: 汉语拼音方案; Traditional Chinese: 漢語拼音方案; Pinyin: Hànyǔ Pīnyīn Fāng'àn), while pin means "spell(ing)" and yin means "sound(s)"), is a system of romanization (phonemic notation and transcription to Roman script) for Standard Mandarin. Hanyu Pinyin was approved in 1958 and adopted in 1979 by the government of the People's Republic of China. It superseded older romanization systems such as Wade-Giles (1859; modified 1912) and Postal System Pinyin, and replaced zhuyin as the method of Chinese phonetic instruction in mainland China.

Since then, Hanyu Pinyin has been accepted by the Government of Singapore, the Library of Congress, the American Library Association, and most international institutions as the preferred transcription system for Mandarin. In 1979 the International Organization for Standardization (ISO) adopted pinyin as the standard romanization for modern Chinese (ISO-7098:1991). Pinyin has become a useful tool for entering Chinese language text into computers.

Pinyin is a romanization and not an anglicization; that is, it uses Roman letters to represent sounds in Standard Mandarin. The way these letters represent sounds in Standard Mandarin will differ from how other languages that use the Roman alphabet represent sound. For example, the sounds indicated in pinyin by b and p are distinguished from each other (by aspiration) in a manner different from that of both English (which has voicing and aspiration) and of French (which has voicing alone). Other letters, like j, q, x or zh indicate sounds that do not correspond to any exact sound in English. Some of the transcriptions in pinyin such as the ang ending, do not correspond to English pronunciations, either.