William Barclay may refer to:William Barclay (jurist) (1546–1608), Scottish jurist
William Barclay (writer), Scottish writer
William Barclay (painter) (1797–1859), English miniature painter
William Barclay (1873–1945), Northern Irish Senator
William Barclay (theologian) (1907–1978), theologian and writer of Bible commentaries
William A. Barclay, New York State Assemblyman
William Edward Barclay (1857–1917), football manager of Everton and of Liverpool
Bill Barclay, American athlete and coach