Zhang Wen-you (张文佑; August 31, 1909 - February 11, 1985), also rendered in English as W. Y. Chang and Zhang Wenyou, was a Chinese geologist. Born in Tangshan, which became the site of a massive earthquake in 1976, Zhang studied civil engineering the Tangshan Institute of Technology and Beijing University. Afterwards, he taught at Guangxi University and the National Central University, which had relocated to Chongqing due to the Second Sino-Japanese War, and became a member of the Academia Sinica's Geological Research Committee. After the war, Zhang traveled and studied in Europe and the United States. Returning to China in the midst of the Chinese Civil War, Zhang initially traveled with the Nanjing government when it retreated to Guangzhou, but decided to stay in mainland China rather than move to Taiwan, quickly becoming the head of the new Institute of Geology at the Chinese Academy of Sciences. He also taught at Beijing University and the newly established Beijing Institute of Geology (now the China University of Geosciences). From the late 1950s, he edited a series of large-scale geological maps of China that became the standard for the field. An accomplished student of languages in addition to his scientific work, Zhang translated works by leading international geologists in Russian and English into Chinese.