It is believed that the deceased include Bangladeshis, Indians and other nationalities.
According to Qassim Civil Defense deputy spokesman Col Abdulaziz Al-Tamimi, the accident occurred near Saqryat Qabra bridge close to Jabal Tamiah, 225 kilometres from provincial capital Buraidah.
The buses were returning to the Eastern Province, Riyadh, and to United Arab Emirates, sources told.
A total 28 emergency rescue teams including six from Madinah and five from Hail region rushed to the accident site, according to Saudi Red Crescent Society Qassim Director Mohammed Al-Hammad.
Some of the victims were treated at the site of the accident while others were transported to hospitals in various governorates including Uqlat Al-Suqour, Al-Nabhaniyah, Al-Ras, Riyadh, Al-Khubaraa and Al-Bakiriyah.
Sixteen of the injured suffered critical injuries while 65 of them had minor injuries.
According to official sources, the accident occurred due to adverse weather conditions in which poor visibility caused the collision.
The accident was handled by the Civil Defense, the Health Affairs Directorate, the Red Crescent, the Traffic Department, the Transportation Directorate and Uqlat Al-Suqour Municipality.