The Mao suit is the western name for the style of male dress known as the Sun Zhongshan suit (中山装, Zhong1shan1 zhuang1, or 中山服, Zhong1shan1 fu2), named after Sun Zhongshan (Sun Yat-sen) who introduced it shortly after the founding of the Republic of China. In accordance with the Chinese tradition of changing the style of dress for different dynasties, Sun Yat-sen instructed that a new suit be designed for the new republic. The western name comes from its popularization by Mao Zedong.

Incorporating elements of German military dress including a turndown collar and four symmetrically placed pockets and based on a suit popular with Chinese men in Japan and Southeast Asia, the Zhongshan suit was an attempt to cater to modern sensibilities without completely adopting western styles. Instead of the three hidden pockets in western suits, the Zhongshan suit had four outside pockets to adhere to the Chinese concepts of balance and symmetry. Over time, minor stylistic changes were made. The suit originally had seven buttons, but this was changed to five buttons.

In the 1920s civil servants of the government were required to wear the Zhongshan zhuang. After the establishment of the People's Republic of China, the suit became a symbol of proletarian unity, and was regularly worn by party cadres until the 1990's when it was largely replaced by the Western business suit.

After Sun Yat-sen's death, popular mythology assigned a revolutionary and patriotic significance to the Zhongshan suit. The four pockets were said to represent the Four Cardinal Principles cited in the classic Book of Changes. The five center-front buttons were said to represent the five Yuans (branches of government) cited in the constitution of the Republic of China and the three cuff-buttons to symbolize the Three Principles of the People.

On Taiwan, the Mao suit was seen infrequently after the 1970's. In Mainland China, the Mao suit remained the standard formal dress for the first and second generation of PRC leaders such as Deng Xiaoping. During the 1990's, the Mao suit began to be worn increasingly infrequently by leaders of Jiang Zemin's generation, who began wearing Western style business suits. In informal occasions, most older cadres will wear panama shirt s and most younger cadres will wear polo shirts. By 2004, the Mao suit was extremely rarely worn even in formal occaisions. The rare occasions in which it is worn usually involve situations in civilian party officials wish to demonstrate control over the military.