The bus was traveling between Casablanca and Ait Attab, a remote area close to Beni Mellal at the base of the High Atlas mountains.
Local authorities said that the bus overturned early on a morning in the province of Khouribga, with a preliminary death toll of 15.
Later, regional health director Rochdi Kaddar increased the number of fatalities to 23, informing AFP that the incident had also injured 36 other individuals.
The injured were taken to a hospital, and an accident inquiry has been started.
In Morocco and other North African nations, traffic accidents—which are frequently fatal—occur frequently.
According to the National Road Safety Agency, Morocco records 3,500 fatalities and 12,000 injuries annually, or 10 fatalities on average every day.
