Cecil's mother has not yet been named.
There are three known timelines involving the Palmer family:
- The main timeline, where Cecil has a sister named Abby and his mother is dead.
- The alternate timeline where Cecil has a brother named Cal and his mother's status is uncertain.
- The alternate timeline where Cecil is an only child and his mother is alive.
Timeline 1 - Main Timeline
Cecil recalls she used to dress him and Abby up in homemade costumes on Halloween and take them trick-or-treating.
It's implied that Cecil's mother was neglectful before she left. Cecil recalls she used to lead him and Abby on walks in the woods, not talking to them and walking faster than they could keep up with, trying to lose them. Cecil also says she used to drop rocks on animals and people as a joke, leading to the death of raccoon and her having to explain death to Cecil. When Cecil breaks his leg, she asks him: “Why are you crying when you don’t even exist?” By Night Vale standards, she may also have not been feeding Cecil and Abby properly. Cecil says that she used to "cook turkey organs" and called them giblets, to which Earl Harlan remarks that this was a lie, Cecil then reflects: "Then what was she feeding us?"
Cecil recalls she used to leave flowers at the base of a giant old tree trunk, never explaining why. It's possible this is the same tree trunk Cecil recalls climbing into, especially considering the focus on Cecil's hearing owls.
She abandoned Abby and Cecil when Cecil was 14 years old, causing Abby to drop out of college and returned home to care for him. Cecil states that this caused a lot of resentment between the two of them and led to them not talking again until their mother died. Their relationship improved further after Janice was born. Cecil said he resented Abby for not being his mother, and instead he came to love Old Woman Josie as a surrogate mother.
Cecil's mother returned to Night Vale when Cecil and Abby were adults. Cecil states that she "lost many battles to herself" including "alcohol, debt, and lack of treatment or even awareness of a mental illness."
Cecil's mother died a few months after returning to Night Vale. Cecil described her death as mundane, implying either natural causes or causes expected based on known risk factors. Abby was present for her death while Cecil was working and found out after the fact.
Timeline 2 - First Alternate Timeline
Little is known about this timeline.
After getting his internship, Cecil states that his mother seems proud of him since she hid from him for 3 days. He also comments that she covered all the mirrors in the house, which he also took to mean she was proud of him. 
Cal says that their mother used to take them to the library to read. Cecil confuses this and the mail timeline, remarking their mother would never put them in that much danger. This implies that Cecil's mother in the main timeline wasn't seriously negligent with Cecil and Abby.
Cecil remembers going camping up near Higgins Lake with his mother, Cal, and some family friends when he was 9 years old.
At some point during Cecil's internship, Cal and his mother disappear and someone uncovers all the mirrors.
Timeline 3 - Second Alternate Timeline
Little is known about this timeline.
Cecil's mother never taught him to fear mirrors, and knows he loves them so much she handed down an antique, full-length mirror he has in the hallway of his studio apartment. She and Cecil talk regularly and get along great. When Cecil asks about the timeline confusions, she remarks "What a dumb question." and he clarifies "She's always been witty like that."
When Cecil takes over as the host of NVCR he states that his mother has been hiding from him for several decades, but that her absence speaks to him more than words.
- Episode 68 "Faceless Old Women": Cecil recalls her saying “You can't learn to love others until you learn that others are fiction, and that self is unreliable.”
- Episode 132 "Bedtime Story": Cecil recounts a bedtime story she used to tell him.
- Episode 108 Cal
- Episode 33 Cassette
- Episode 110 Matryoshka
- Episode 171 Go to the Mirror?
- Episode 26 Faceless Old Women
- Episode 106 Filings
- Episode 176 The Autumn Specter
- Episode 182 It Sticks With You
- Episode 95 Zookeeper
- Episode 78 Cooking Stuff: Thanksgiving Special
- Live show "Ghost Stories"
- Episode 70B Review
- Episode 56 Homecoming
- Episode 67 Best Of?