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 her father started their father-daughter wedding dance.
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".
- Paternal Grandfather: Unnamed
- Paternal Grandmother: Unnamed
- Maternal Grandmother: Unnamed
- Maternal Grandfather: Unnamed
- Father: Wyatt
- Mother: Susan
- Sister: Penny Hofstadter
- Brother: Randall
- Uncle: Unnamed
- Cousin: Unnamed
- Husband: Unnamed
- Possible son/nephew: Unnamed
- Brother-in-law: Leonard Hofstadter
- 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.