Two different juries were unable to reach a verdict against Kathia Davis.
The female suspect was convicted of four felony counts of unlawful sexual intercourse and two misdemeanor counts of contributing to the delinquency of a minor last August.
The divorced mother of three was found guilty of sexually assaulting a second boy, her son's 16-year-old friend. Davis reportedly had sex with the 16-year-old in the summer of 2010 and in the summer of 2011.
Davis already faces up to five years in prison on the charges she has been convicted of. If she is convicted in the third trial, she can face up to an additional 11 years in prison.
Davis acknowledged having sex with the 16-year-old but insisted that she had to rebuff the advances of the 13-year-old.
Investigators say she hosted drinking parties for her son's hockey team at her home in Laguna Niguel. Davis would provide the boys alcohol and then seduce the boys, according to prosecutors.
Davis is due in court for a pretrial hearing on May 28.