William J. MacDonald may refer to:
William J. Macdonald (filmmaker), American film and television producer and writer William James Macdonald (1851–1941), Scottish mathematician and schoolteacher William Jesse McDonald (1852–1918), Texas Ranger William John Macdonald (1832–1916), Canadian merchant and politician William Johnson McDonald (1844–1926), American banker who endowed an astronomical observatory William Joseph McDonald (1904–1989), Irish-born bishop of the Catholic Church in the United States William Josiah MacDonald (1873–1946), Michigan politician
See also William MacDonald (disambiguation)