Loreintz Rosier (born 14 August 1998) is a French professional footballer who plays as a defensive midfielder for Eredivisie club Fortuna Sittard.

Born at Gonesse in France, of Guadeloupean and Italian descent, Rosier started playing football at the age of 6 at Saint-Brice FC.

He then moved to Le Bourget FC and later AAS Sarcelles to play at the highest youth level.

In 2013, he signed a three-year youth contract with SM Caen, but decided to leave the club after two season following disputes.

On 23 September 2018, Rosier made his professional debut with Vitória Guimarães B in a 2018–19 LigaPro match against Leixões.