The group entered pleas Wednesday through their attorneys in a Los Angeles court. All four are charged with felony burglary counts.
The suspects include 19-year-olds Nicholas Prugo, Diana Tamayo and Courtney Leigh Ames and 27-year-old Roy Lopez Jr.
Prugo faces seven counts of first-degree burglary for break-ins at the homes of stars including Lindsay Lohan, Paris Hilton, Orlando Bloom and Rachel Bilson.
They each are individually represented by private attorneys. Prugo's lawyer, Sean Erenstoft, asked that his client's case be separated from the others. A court commissioner denied the request, saying it was premature.