It happened a little before 8 p.m. on Highway 59 about eight miles south of Atchison.
The two were in an S-10 pick-up southbound on Hwy. 59 when they came upon a no-passing zone.
"The small S-10 pick-up was in front of the camper, trying to make a left turn," said Atchison County Sheriff Jack Laurie. "The semi proceeded around both those vehicles. When the S-10 vehicle pulled out into the intersection, the semi struck him."
Laurie said it was a non-passing zone.
He said the injuries were non-life threatening.
The Kansas Highway Patrol is investigating the crash.