McIsaac is a surname. Notable people with the surname include:
Alan McIsaac (born 1954), Canadian politician Angus McIsaac (1842–1902), Canadian politician Billy McIsaac (born 1949), Scottish musician Cliff McIsaac (1930–2006), Canadian politician Colin Francis McIsaac (1854–1927), Canadian politician Hazel McIsaac (1933–2012), Canadian politician Hilary McIsaac (1820–1901), Canadian politician James McIsaac (1854–1927), Canadian politician John L. McIsaac (1870–1941), Canadian politician Justin McIsaac (born 1978), American wrestler Shona McIsaac (born 1960), Scottish politician Tai McIsaac (born 1975), Australian rugby union player