The Highland club has also dispensed with the services of Adams' father, George, who was director of football.
A brief statement on the club's official website confirmed all parties had "come to an agreement".
"Ross County FC and their Manager and Director of Football, Derek and George Adams, have come to an agreement, whereby they will part ways, effective from today," Thursday's statement read.
"Chairman Roy MacGregor wishes to recognise the contribution both have made to the journey that Ross County FC have made over their years with the club and wish both well in their future careers.
"Further details of the club’s continuing restructuring will be made available as plans are ratified over the following days."
Adams had two spells as a player with County, before taking the reins in 2007, winning the Second Division and earning promotion to the First Division
He left three years later to join Hibernian as an assistant to Colin Calderwood but returned the following May and masterminded promotion to the Scottish Premier League,
Adams had signed a new deal at the end of the 2012/13 season to extend his second spell in charge to 2016 but a fightback League Cup win over Stranraer at the weekend was not enough to buy the 39-year-old more time in the Premiership.
George Adams took over as director of football in 2005, following youth development roles at Motherwell, Celtic and Rangers.