Zhang Daqian (simplified Chinese: 张大千; traditional Chinese: 張大千; pinyin: Zhāng Dàqiān; Wade–Giles: Chang Ta-Chien) (May 10, 1899 - April 2, 1983) was one of the best-known and most prodigious Chinese artists of the twentieth century. Originally known as a guohua (traditionalist; 國畫) painter, by the 1960s he was also renowned as a modern impressionist and expressionist painter. Chang is regarded as one of the most gifted master forgers of the twentieth century.

Born in a family of artists in Neijiang, Sichuan, China, he studied textile dyeing techniques in Kyoto, Japan and returned to establish a successful career selling his paintings in Shanghai. A staunch supporter of the Kuomintang, he left China in 1948 and moved to Mogi das Cruzes, Brazil, and then to Carmel, California, before finally settling in Taipei, Taiwan.

A meeting between Chang and Picasso in Antibes in 1953 was viewed as a summit between the preeminent masters of Eastern and Western art. The two men exchanged paintings at this meeting.

Chang's forgeries are difficult to detect for many reasons. First, his ability to mimic the great Chinese masters:

So prodigious was his virtuosity within the medium of Chinese ink and colour that it seemed he could paint anything. His output spanned a huge range, from archaising works based on the early masters of Chinese painting to the innovations of his late works which connect with the language of Western abstract art.

Second, he paid scrupulous attention to the materials he used. "He studied paper, ink, brushes, pigments, seals, seal paste, and scroll mountings in exacting detail. When he wrote an inscription on a painting, he sometimes included a postscript describing the type of paper, the age and the origin of the ink, or the provenance of the pigments he had used." Third, he often forged paintings based on descriptions in catalogues of lost paintings; his forgeries came with ready-made provenance.

Chang's forgeries have been purchased as original paintings by many major art museums in the United States, including the Museum of Fine Arts, Boston:

Of particular interest is a master forgery acquired by the Museum in 1957 as an authentic work of the tenth century. The painting, which was allegedly a landscape by the Five Dynasties period master Guan Tong, is one of Zhang’s most ambitious forgeries and serves to illustrate both his skill and his audacity.

James Cahill, professor emeritus of Chinese art at the University of California, Berkeley, has claimed that the painting "The Riverbank," a masterpiece from the Southern Tang Dynasty attributed to the 10th century painter Dong Yuan, held by the New York Metropolitan Museum of Art, is likely another Chang Dai-chien forgery.

Museum curators are cautioned to examine all questionable Chinese paintings of all genres with the query, "Could this be by Zhang Daqian?" Joseph Chang, curator of Chinese art at the Sackler Museum, posited that practically every notable collection of Chinese art contains a forgery by the master painter.