The Syrian Observatory for Human Rights said it had documented the deaths of 76,021 people.
Of the total, 17,790 were civilians, including 3,501 children.
Additionally, more than 15,000 rebel fighters were killed, as were nearly 17,000 militants from jihadist groups, including the Islamic State and Al-Nusra Front, Al-Qaeda's Syrian affiliate.
At least 22,627 government forces - both soldiers and members of pro-government militias - were killed, the Britain-based group said.
More than 200,000 people have been killed since the conflict began in March 2011 with anti-regime protests that spiralled into a war after a government crackdown.