Clair Sprague Tappaan (May 14, 1878 – November 30, 1932) was an American lawyer, professor and jurist who was on the faculty of the University of Southern California Law School from its formation as an official school of the university in 1904 until 1928, and served as a judge of the Los Angeles County Superior Court and California Court of Appeal from 1927 until his death in 1932.
In 1901, he played on the football team of the Los Angeles Athletic Club, and the same year he served as coach of the USC football team, which played only one game – a 6-0 road loss to Pomona College.
In August 1927 he was appointed to the Superior Court by Governor C. C. Young, and he was elected to a full term in September 1928.
His death was ruled the result of chronic myocarditis and sclerosis of the left coronary artery.
Tappaan was a longtime official of the Sierra Club, serving as its fifth president from 1922 to 1924, and on the board of directors from 1912 until his death.