The preliminary hearing for 37-year-old Rozalyn Joy Prairie Chicken started Friday in Lethbridge provincial court.
But no witnesses showed up, so the judge agreed to stay the charges.
Last June, Prairie Chicken was charged with sexual assault and sexual interference.
Police were called to a disturbance at a north side Lethbridge home and were told that a teenage boy had allegedly been sexually assaulted by an adult female acquaintance a few months earlier.
A stay means that charges can be reactivated within a year if new evidence comes to light.