The Centre Daily Times reports Bianca Jeanty and Felicia Ragsdale entered pleas in Centre County court on Thursday.
Both testified last week in the trial of a third student, Hanif Johnson, who was convicted on summary harassment charges.
Jeanty pleaded guilty to misdemeanor simple assault. Ragsdale pleaded guilty to disorderly conduct and harassment.
All three were indefinitely expelled by Penn State; Ragsdale and Johnson were held from graduating in 2012.
A Penn State spokeswoman says Ragsdale and Johnson were permitted to graduate in the spring; Jeanty has been cleared to return to school.
Prosecutors say the victim was slapped, punched and kicked while pledging Omega Essence, a "little sisters" group.
Information from: Centre Daily Times