The Battle of Debre Abbay, also known as the Battle of Mai Islami, was a conflict between Ras Marye of Yejju, Regent of the Emperor of Ethiopia, and his rival from Tigray, Dejazmach Sabagadis of Agame. Although Ras Marye lost his life in the battle, Dejazmach Sabagadis was defeated and executed by Ras Marye's followers after surrendering.

Marye of Yejju (died 14 February 1831) was a Ras of Begemder and Enderase (regent) of the Emperor of Ethiopia. He was the brother of his predecessor Ras Yimam.

The missionary Samuel Gobat had a low opinion of Marye. He wrote in his journal, "A character worse then [sic?] is attributed to Mariam [Marye], cannot be well given to a prince. He does justice to none. Far from punishing a soldier for robbing or killing his companion, he publicly commends him, as a man of courage. It is said that he has ordered all of his soldiers, on entering Oubea's territories, to kill every human being they meet, without distinction of age or sex; threatening with death the soldier, known to have spared a single person in his power." However, Gobat's opinion may have been influenced by a raid Marye's men made on Gondar 14 May 1830, which he described immediately before this passage.