The 18-year-old, who can't be named because of her age at the time of the killing, was accused of fatally stabbing Ashlee Hyatt at a house party in Peachland, near Kelowna, in June 2010.
A jury has found the accused guilty of manslaughter, but not guilty of second-degree murder or assault.
The accused testified in her own defence, and her lawyer told the jury Hyatt's death was an accident.
The Crown alleged the accused pulled a knife during what was a consensual fight between her and Hyatt.
The young woman who killed Hyatt was originally charged with first-degree murder, but that was later reduced to second-degree murder, before the jury finally settled on manslaughter.