The Phnom Penh Municipal Court on Friday sentenced each of three men to three years in jail and four million riel ($1,000) fine for chasing and beating Professor Suy Sareth.
Other suspects are still at large, court spokesman Suos Vichea Randy said.
The three men used violence against Sareth, who works for the National University of Management, following a traffic accident on March 11.
The three were charged with Intentional Acts of Violence with aggravating circumstances under Articles 218 and 411 of the Criminal Code.
The accused were identified as An Phally, 34; Yat Tithya, 21; and An Vin Ty, 21.