Janet Williams is an inmate at Wentworth Detention Center serving from ep 599-639. Nicknamed Maggot, first seen in (599). When Lou Kelly plots to injure herself to avoid being sent to Blackmoor, Janet helps her by distracting Mervin , while Lou steals a knife from the kitchen (606). She helped Lou Kelly frame Alice Jenkins and Rita Connors for a fake murder attempt. She was transferred from Blackmoor in episode 613. She overhears Bob Moran talking to Kath Maxwell and tells Lou what she knows, planning to use the information to force Bob to help them escape. Lou double crosses her. For this Janet ends up killing Lou Kelly. After Lou Kelly is found murdered in solitary, Janet is interviewed by police and tricked into admitting that she killed Lou (617). She is the umpire for the volleyball game. 

Janet then joins forces with Kath Maxwell (621) and makes her provide the cash for them to buy support and weapons. Janet's sister Sandra is enlisted to bring in drugs (624) and Janet and Kath are involved in selling it to the women. Contrary to Kath's wishes, Janet tries to antagonize Merle Jones into attacking Rita, and persuades Merle to hand over her medication to her rather than take it (637). When Kath finds out about this, she bashes Janet, but Joan Ferguson has set them both up, and Janet is transferred to A Block.

Christine Earle had previously appeared as Kathy Freeman in the series.