Ch'ing-k'un Yang (Chinese: 楊慶堃; pinyin: Yáng Qìngkūn; 1911 – 10 January 1999), better known as C. K. Yang, was an American sociologist who supported the application of sociological theory to the study of China. He was known for his contributions to the study of Chinese religion and his argument that religion in China was "diffuse" and present in many aspects rather than being institutionalized in churches.

Yang was born in Guangzhou and educated at Yenching University, where he became interested in the study of sociology, and taught for much of his career at the University of Pittsburgh, where he trained American and Chinese sociologists and used periodic leaves of absence to build sociology programs in Hong Kong and the People's Republic of China.

In 2007, friends and colleagues published a festschrift in his memory, Social Change in Contemporary China: C. K. Yang and the Concept of Institutional Diffusion.

Born in 1911 in Canton, where his father owned both a wholesale fish market and land in the countryside, Yang was tutored at home in the Confucian classics. Over his father's objections, Yang decided to end his home tutoring and enter Yenching University, where he shared a room with Fei Xiaotong, who was to become China's leading anthropologist. The American sociologist Robert E. Park spent the year 1931 at Yenching, strengthening Yang's ambition to become a sociologist himself. Yang, Fei, and Wu Wenzao translated a collection of Park's sociological essays published by the Yenching Department of Sociology in 1934. After receiving his bachelor's and master's degrees from Yenching, Yang went to the United States and took his PhD in sociology at University of Michigan in 1939.

In December, 1939, he married Louise Chin, a Chinese-American whose parents operated a laundry in Queens. She graduated from Barnard College, earned a degree in Social Work from University of Pittsburgh, and worked for many years in the Pittsburgh public school system. The couple had two sons, Wallace and Wesley.

The first job Yang held after earning his PhD was as editor of the Chinese Journal, a New York City publication for which he investigated crime and local news in the Chinese American community. He then became an assistant professor at University of Washington, Seattle, where he taught from 1944 to 1948. In 1948, he became head of the sociology department at Lingnan University in Canton. Yang told an American friend that he could work with the new government because he agreed with them that foreign domination of China had to end. He and a group of his students did field studies in a nearby village. His eye-witness accounts became part of the books he published later, A Chinese Village in Early Communist Revolution and The Chinese Family in the Communist Revolution. Yang also worked with another group to translate articles written by Mao Zedong into English. But in 1951, after the outbreak of the war in Korea turned into a confrontation with the United States, Yang was warned that he would be arrested if he did not leave.

In 1951 Yang took his family to live in the United States, where he was research associate at the MIT Center for International Studies in 1951 and at Harvard in 1952. He became associate professor of sociology at University of Pittsburgh in 1953, full professor in 1958, and retired from Pittsburgh in 1981. He died on January 10, 1999.

Yang's first study published in English, A North China Local Market Economy (1944), summarized his pre-war field work in Zouping County, the site of Liang Shuming's work in rural reconstruction. Though brief, the study is considered a groundbreaking work.