The Big Bang Theory Wiki

Lisa is the sister of Penny and Randall and the other daughter of Wyatt and Susan. She never appeared on the show, unlike her parents and brother. She is possibly the mother of the nephew Penny mentions having (and bought a comic book from Stuart Bloom for him). It is also mentioned that she shot her husband while they were both drunk, though it is also never implied if the shooting resulted in death or injury.

When Penny was talking to her mother about her engagement to Leonard in "The Status Quo Combustion", it was implied that her sister was pregnant when she got married, which is later confirmed in "The Bachelor Party Corrosion" where Penny mentions that her water broke at the wedding reception after she and Wyatt began their father-daughter wedding dance.

She also saw Penny's boyfriend's blog on her sex life and contacted Penny in "The Tangerine Factor".

In "The Parking Spot Escalation", she is mentioned to have given her sister her first bikini wax using melted crayolas and duct tape. The experience traumatized Penny to the point that she can no longer see a box of crayons without crossing her legs.

Her name was finally revealed in "The Donation Oscillation".



  • Lisa, her husband and possible son/nephew were, unfortunately, absent from Leonard and Penny's wedding redo. It is unknown why. Either the writers forgot Penny has a sister, a brother-in-law and nephew or because of a limited episode budget for actors and actresses.