Iqbal Nezami, spokesman for the provincial police chief, said that four other civilians were wounded after their vehicle was attacked near Faroz Koh, the provincial capital, on Tuesday morning, AP reported.
The victims were all ethnic Hazaras, a Shia minority in Afghanistan that is frequently targeted by extremists in different parts of the country.
Nezami said the Hazaras were on traveling from Herat, another western province, to Ghor when they came under attack.
No one immediately claimed responsibility for the attack.
Both the Taliban and militants from the rival Daesh (ISIL or ISIS) terrorist group are active in Ghor and have previously claimed attacks in the province.