The accident occurred at 5:50 pm (1450 GMT) Monday at Maungu, 360 kilometers (220 miles) from the capital Nairobi, when the students from Kenyatta University were traveling to the coastal town of Mombasa.
Ten people died on impact and another died later in hospital, police said, adding that 42 people were seriously injured.
"The driver of (the) university bus was overtaking a fleet of motor vehicles and as it was raining heavily, the bus skidded to the right side of the road," the police report said.
This "prompted the driver of the truck to avoid head on collision, hence hitting the left side of the university bus," it added.
The bus was carrying 58 people on an academic trip.
The injured were taken to a hospital in the nearby town of Voi, the Kenyan Red Cross said on X, formerly Twitter.
Kenyatta University said on Tuesday it was "deeply saddened" by the accident and had set up a help desk at the main campus to provide "assistance during this challenging time."
"Some of the injured students are in the process of assessment for possible evacuation to Nairobi," it said.
Road accidents are common in the east African nation, where road conditions are often poor and traffic regulations violated or ignored.
According to figures by the National Transport and Safety Authority, 4,324 people were killed and 18,561 injured in 2023 in road accidents in Kenya, down 7.8 percent from the previous year.
However, the start of 2024 was deadly, with 536 people killed between January 1 and February 11, a five-percent rise over a similar period last year.
The most high-profile incident led to the death on February 11 of 24-year-old world marathon record holder Kelvin Kiptum.
Five people were killed and 18 others injured Tuesday when their van rammed a tractor in western Kenya.
On Saturday, a high school student and a teacher died when their bus with 63 on board lost control and rolled several times down a slope.
Forum