The court on Monday sentenced eight of the defendants to 20 years of imprisonment for killing "at least 200 prisoners of war" in the hamlet of Ovcara near Vukovar during a three-month siege of the northeastern Croatian town.
Three men were sentenced to 15 years, one defendant was sentenced to 12 years, one woman to nine years and one to five years in jail, while two defendants were cleared of charges.
The trial in Serbia's special war crimes court opened in March last year.
Vukovar was captured by the Yugoslav army and Serb rebels in November 1991 at the end of the siege.
The town was then razed and more than 1000 civilians were killed, including those at Ovcara, 192 of whom have been identified.
After the war ended, the Vukovar region was put under UN administration and was reintegrated into Croatia in 1998.
The International Criminal Tribunal for former Yugoslavia based in The Hague has been trying three Serb officers - Veselin Sljivancanin, Miroslav Radic and Mile Mrksic - with war crimes committed in Vukovar.