Prime Minister Keith Mitchell (search) was among the legislators lauding the former president, who died June 5 at age 93. Lawmakers approved a motion saying Reagan played a significant role in restoring peace and democracy.
The Caribbean island became a point of contention in the Cold War after Maurice Bishop (search) led a bloodless coup and installed a Marxist government in 1979.
In October 1983, a radical faction of the government staged a coup, and a firing squad killed Bishop and 10 supporters.
"At the initiative of former Governor General Sir Paul Scoon and several Caribbean leaders, a request was made to President Reagan for urgent military intervention in Grenada to restore peace and stability," Mitchell said. "President Reagan responded positively and decisively to the request and intervened militarily."
Six days after Bishop's killing, Reagan ordered the invasion and U.S. troops led a force that included soldiers from nearby islands.
Reagan said the purpose was to restore order and protect American interests, particularly the lives of hundreds of American medical students.
Reagan also ordered the invasion because his administration suspected Grenada's airport was going to become a joint Cuban-Soviet base. Cuba insisted it was helping build the airport for civilian uses only.
Some details from the 1983 invasion, including the number of Grenadians killed, remain unclear. The U.S. government says 45 Grenadians, 24 Cubans and 19 U.S. troops were killed.
Bishop's body remains missing, as do those of more than a dozen other coup victims.
Wednesday's special session followed a Tuesday church service at which about 100 people, including U.S. Ambassador Nadia Tongur, honored Reagan.