Momcilo Perisic, 67, was sentenced after he was convicted by the International Criminal Tribunal for the former Yugoslavia. He had pleaded not guilty.
Perisic was chief of staff of the Yugoslav Army during the wars in Bosnia and Croatia in the 1990s.
During his trial at The Hague, Netherlands, prosecutors said Perisic provided troops, weapons and financial support to ethnic Serb armies in support of their activities in Bosnia and Croatia, including the siege of Sarajevo and the 1995 Srebrenica massacre, in which over 7,000 Bosnian Muslims were slaughtered.
The tribunal acquitted him of charges that he was directly responsible for crimes as a superior officer to the commanders of the Bosnian Serb forces.
The court said Perisic "did not exercise effective control over Ratko Mladic or any other Yugoslav Army officer serving in the [Republika Srpska Army] … but that he did have effective control over the officers in the Republic of Serb Krajina Army, which shelled Zagreb in May 1995," Tanjug reported.
The sentencing is the first imposed in a case against an official of the former Federal Republic of Yugoslavia for crimes committed in Bosnia and Herzegovina, the tribunal said.