The shootings took place at a mobile home park where families had gathered in one trailer to celebrate.
“The suspect, a boyfriend of one of the female victims, drove to the residence, walked inside and began shooting people at the party before taking his own life,” the Colorado Springs Police Department said.
The motive for the attack is not known.
The victims were all adults, but a number of children were present in the trailer at the time.
The identities of the victims and the attacker have not yet been released.