The IRFU hailed former Ireland skipper Dawson as an "iconic figure" and revealed that he died on Friday.
Dublin-born Dawson played six Tests as Lions captain and guided the team to their only win at New Zealand's Eden Park stronghold in 1959.
The former Leinster hooker played 27 times for Ireland from 1958 to 1965, as well as representing the Barbarians.
Dawson was part of the Lions coaching set-up in 1968 and also became Ireland's first national-team coach in 1969, a role he held for three years.
IRFU chief executive Kevin Potts paid tribute to Dawson, saying: "Ronnie Dawson was an iconic figure in Irish and international rugby whose impact transcended many eras.
"He was a quintessential leader and leaves a lasting legacy which will never be forgotten."
