It happened at an apartment in the 12600 block of Richmond Avenue near Dairy Ashford around 11:30 p.m.
The fight between the two escalated when relatives and friends got involved and shots were fired, according to Houston police.
The boyfriend was killed in the shooting. The 11-year-old was shot in the hand, police said.
Another person was also shot in the side and was transported to a hospital. Their condition wasn't immediately known.
Investigators were working to determine who was responsible for the shooting.