Victoria Cavaricci said robbers accosted her 18-year-old daughter and a male friend early Wednesday on a sidewalk in a neighborhood about seven miles northwest of the Las Vegas Strip.
Las Vegas police confirmed the robbery had occurred and said they were investigating.
"She's not physically harmed, but she's in a panic," Cavaricci told The Associated Press in a brief phone interview from her Las Vegas home. Cavaricci said the robbers took a cell phone and $5.
Gordon reached the finals of the 2005 "American Idol" singing competition. She graduated from a Las Vegas high school and now lives in Los Angeles.
Cavaricci said her daughter was unable to talk with a reporter early Thursday.
"American Idol" airs on FOX, which is owned by the parent company of FOXNews.com.