Lance Herbert Barnard AO was an Australian politician and diplomat. He was the deputy leader of the Australian Labor Party (ALP) from 1967 to 1974 and held senior ministerial office in the Whitlam government, most notably as the third deputy prime minister of Australia from 1972 to 1974.

The Whitlam government was the federal executive government of Australia led by Prime Minister Gough Whitlam of the Australian Labor Party. The government commenced when Labor defeated the McMahon government at the 1972 federal election, ending a record 23 years of continuous Coalition government. It was terminated by Governor-General Sir John Kerr following the 1975 constitutional crisis and was succeeded by the Fraser government—the sole occasion in Australian history when an elected federal government was dismissed by the governor-general.