The daughter of a co-founder of the Nxivm “sex cult” has pleaded guilty to racketeering conspiracy in federal court in Brooklyn.

Lauren Salzman, 42, entered her plea Monday, two weeks after her mother, Nancy, 64, admitted her own guilt. They are the first two to plead guilty in the case.

The transcript of the plea by Lauren Salzman was immediately sealed and would be redacted before being made available to the public, officials said, fueling speculation that the two may cooperate during a trial set for April 29.

The daughter was a high-level sex “master” in the upstate-based group, the feds have said.

The invite-only, master-slave cult was disguised as a legitimate executive self-help organization, but was secretly controlling women through extortion and intimidation, grooming them for the sexual gratification of co-founder Keith Raniere, the feds allege.

Other cult leaders included “Smallville” actress Allison Mack and Seagram’s heiress Clare Bronfman, the feds allege.

Lauren had been asking to be tried separately from her mother, who she argued faced far higher charges and would make her look bad to jurors by association.

Nancy Salzman pleaded guilty on March 13, crying as she admitted destroying evidence and hacking into emails of the group’s perceived enemies.

She had apologized, during her plea, for having dragged her daughter into the group.

“I am deeply sorry for the trouble I caused my daughter, [and] the pain I caused my parents.”