The 1st (Emperor Alexander) Guards Grenadiers (Kaiser Alexander Garde-Grenadier-Regiment Nr. 1) were an infantry regiment of the Royal Prussian Army. The regiment was formed in 1814 and was named after Czar Alexander I of Russia, who was also its first colonel-in-chief. The regiment was disbanded in 1920 with the 9th and 12th company of the Infantry Regiment 9 Potsdam bearing its tradition in the new Reichsheer.