| Heinrich XX | |
|---|---|
| Prince Reuss of Greiz | |
 Lithograph by G. Weinhold, 1841. | |
| Born | 29 June 1794 Offenbach, Landgraviate of Hesse-Darmstadt |
| Died | 8 November 1859 (aged 65) Greiz, Principality of Reuss-Greiz |
| Spouse | Princess Sophie of Löwenstein-Wertheim-Rosenberg Princess Caroline of Hesse-Homburg |
| Issue | Christiane, Princess Hugo of Schönburg-Waldenburg Prince Heinrich XXI Heinrich XXII, Prince Reuss of Greiz Prince Heinrich XXIII Marie, Countess Friedrich of Ysenburg and Büdingen in Meerholz |
| House | House Reuss of Greiz |
| Father | Heinrich XIII, Prince Reuss of Greiz |
| Mother | Princess Wilhelmine Louise of Nassau-Weilburg |
Heinrich XX, Prince Reuss of Greiz (German: Heinrich XX Fürst Reuß zu Greiz; 29 June 1794 – 8 November 1859) was Prince Reuss of Greiz from 1836 to 1859.