Dr. William Christian Lehmann, 91, a professor emeritus of sociology at Syracuse University who had lived in Washington since 1966, died Nov. 23 at Georgetown University Hospital. He had cancer.

He was on the faculty of Syracuse University's sociology department from 1927 until retiring in 1954. He also had taught courses at several other schools, including Tulane University. He was an instructor at universities in West Germany in the 1950s and at Japanese universities in the early 1960s.

Dr. Lehmann was the author of a number of works on figures of the Scottish Enlightenment, including "Henry Home and the Scottish Enlightenment." He also was the author of "Scottish and Scotch-Irish Contributions to Early American Life and Culture," published in 1978.

Dr. Lehmann was born near Slater, Iowa, and was a 1910 graduate of what is now Lakeland College in Sheboygan, Wis. He earned a master's degree and a divinity degree at Vanderbilt University and earned his doctoral degree in sociology at Columbia University in 1930.

His wife, Jane S. Lehmann, died in 1979. Dr. Lehmann's survivors include a son, Dr. William L. of Albuquerque, N.M.; a daughter, Dr. Shirley Spohr of Washington; a brother, Fred, and a sister, Ann Smith, both of Iowa; seven grandchildren and two great-grandchildren.