Lieutenant-Colonel John Blackadder (14 September 1664 – 31 August 1729) was a Scottish soldier who served with the Cameronian Regiment during the late seventeenth and early eighteenth centuries. The fifth son of dissenting minister John Blackadder, he was a devout Calvinist, and joined the Cameronians – a predominantly religious regiment – as a volunteer cadet when they were raised in 1689 to fight for King William III. He soldiered with the regiment through the campaign in Flanders, where he was court-martialled and later pardoned for killing an officer in a duel, and then during the War of the Spanish Succession. He was wounded at the Battle of Blenheim, and twice wounded at the siege of Lille; after the Battle of Malplaquet he was promoted to lieutenant-colonel, and took command of the