The strike trio have extended their current deals by two years, keeping them with the Dingwall club until May 2017.
Curran, 25, has scored five goals in 15 games since joining County in January, while 24-year-old former Werder Bremen forward Boyce has netted eight times following his summer arrival from Cliftonville.
Highly-rated academy product MacLeod is yet to make a first-team appearance for County.
Manager Jim McIntyre said: “I am pleased that Ross County have secured Liam, Craig and Kyle on two-year extensions, which is very good for the club and the players.
“Liam and Craig have been in great form in the first team and local lad Kyle has shown a lot of promise coming through our youth development system.”