Philadelphia police say Shalaya Porter was last seen June 5 near 46th Street and Fairmount Avenue.
Her mother, grandmother, aunts and a teacher gathered outside Motivation High School at 59th Street and Baltimore Avenue on Tuesday to hand out flyers and bring attention to her story.
They say it's unusual the teen disappeared without her cellphone and missed her graduation.
Porter was preparing to go to Morgan State University in the fall.
"I love you baby. Just please come home. We had so many plans. I'm supposed to be going to college with you," her mother Kaleia Porter said through tears.
Shalaya Porter is described as 5'6, 120 pounds, medium build, brown eyes, light brown complexion, black hair and a nose piercing.
Anyone with any information on her whereabouts is asked to contact the Southwest Detective Division at 215-686-3183 or 911.