Los Angeles Superior Court Judge Edmund Clarke Jr. ruled that Thomas Brodnicki, 46, "lacked specific intent" to cause Gomez fear, said District Attorney spokeswoman Sandi Gibbons.
She said prosecutors were now "evaluating our next step."
Brodnicki pleaded not guilty earlier this month to one felony charge alleging that he stalked the 19-year-old entertainer between July and October.
Another judge in the case earlier had granted a stay-away order against Brodnicki in October. Brodnicki allegedly told a psychiatrist he traveled to Los Angeles to see Gomez and had conversations with God about killing her, according to court documents.
Gomez is best known for her work on children's shows such as "Wizards of Waverly Place." She also is the girlfriend of teen singer Justin Bieber.
