Lucia Perez, 16, died earlier this month in the city of Mar del Plata.
Two men who dropped her off at a hospital on 8 October, freshly washed and dressed, said she had overdosed on drugs. But doctors found evidence of extreme sexual violence.
A march will begin at 17:00 local time (20:00 GMT) in the capital, Buenos Aires.
Activist groups are calling on women to wear black when they walk out of their places of work for an hour at midday on Wednesday (14:00 GMT). They are calling the actions Miercoles Negro - Spanish for Black Wednesday.