The Battle of Mărăști was one of the main battles to take place on Romanian soil in World War I. It was fought between 22 July and 1 August 1917, and was an offensive operation of the Romanian and Russian armies intended to encircle and destroy the German 9th Army. The operation was planned to occur in tandem with the Nămoloasa offensive; however, this operation was abandoned before it began.

The 9th Army was an army level command of the German Army in World War I. It was formed in September 1914 in Breslau to command troops on the southern sector of the Eastern Front. The army was dissolved on 30 July 1916, but reformed in Transylvania on 6 September 1916 for the Romanian Campaign. It was transferred to the Western Front on 19 June 1918 where it was finally dissolved on 18 September 1918.