Mamia I Dadiani (Georgian: მამია I დადიანი; died 1345) was a member of the House of Dadiani and eristavi ("duke") of Odishi in western Georgia from 1323 until his death.
Mamia succeeded as duke of Odishi, latter-day Mingrelia, on the death of his father, Giorgi I Dadiani, in 1323. This was the time when a civil war was raging in the Kingdom of Imereti, of which Odishi was part, between King Constantine and his brother Michael. According to the early-18th-century historian Prince Vakhushti, this situation was exploited by Giorgi I Dadiani to assert the Dadiani's autonomy, which was further consolidated by Mamia I. By that time, he held sway not only over Odishi proper; his influence extended south into Guria and north into Abkhazia. In 1330, however, Imereti and its vassal principalities were reintegrated by the resurgent King of Georgia, George V "the Brilliant", to whom Dadiani offered his submission. Mamia died in 1345 and his son, Giorgi II was confirmed by the king of Georgia as his successor.[1][2]