Matthew I (French: Mathieu de Montmorency; died 1160) was lord of Montmorency, Marly, Conflans-Sainte-Honorine and Attichy.
He was also Constable of France from 1138 to 1160 under Louis VII.
[1] He was the eldest son of Bouchard IV de Montmorency and Agnes de Beaumont-sur-Oise.
[2] In 1126 he married Alice FitzRoy (Alix), illegitimate daughter of King Henry I of England,[3] and had the following issue: Alix died before 1141.
Matthew then married Adelaide of Maurienne, the widow of Louis VI of France.