Henry I (died 8 October 1291) was a Prince of Mecklenburg-Werle and Mecklenburg-Güstrow.
He was the son of Prince Nicholas I of Mecklenburg-Werle and his wife Princess Jutta of Anhalt the daughter of Prince Henry I of Anhalt and his wife Princess Irmgard of Thuringia.
[1][better source needed] Henry and his brother John ruled Mecklenburg-Werle jointly following the death of their father on 10 May 1277.
[2] Henry and his brother ruled jointly until 1283 when Henry founded the principality of Mecklenburg-Güstrow while John took up residence in the principality of Mecklenburg-Parchim which he ruled jointly with Prince Pribislaw II.
[1] Henry was married twice; firstly in 1262 to Rikissa Birgersdotter (died 1288), with the following children: He was married secondly in 1291 to Matilde of Brunswick-Lüneburg (died 1302) the daughter of John of Brunswick, Duke of Lüneburg.