Johann Karl August, Count of Leiningen-Dagsburg-Falkenburg (German: Johann Karl August von Leiningen-Dagsburg; 19 March 1662 in Schloss Broich, Mülheim an der Ruhr – 13 November 1698 in Schloss Broich) was a German nobleman.
By descent, he was Count of Leiningen and Dagsburg, by heritage, he was Lord of Broich and Bürgel.
Johann Karl August was a son of Count George William of Leiningen-Dagsburg (8 March 1636, Heidesheim am Rhein – 18 July 1672, Oberstein) and his wife, Countess Anna Elisabeth von Daun-Falkenstein (1 January 1636 – 4 June 1685, Schloss Broich), daughter of William Wirich, Count of Daun-Falkenstein (1613–1682) and Elisabeth von Waldeck-Wildungen (1610–1647).
On 13 December 1685 married at Babenhausen Castle with Johanna Magdalena (18 December 1660, Bischofsheim am Hohen Steg – 21 August 1715, Hanau), daughter of Johann Reinhard II of Hanau-Lichtenberg (1628–1666) and his wife, Anna Magdalena, Countess Palatine of Zweibrücken-Birkenfeld (1640–1693).
They had the following children: