Olivia Caldwell is a woman who Spencer Hastings believed to be her real mother. Later, Spencer found out that she was actually her surrogate mother.
Olivia has emerald green eyes, dirty blonde hair, and a slim figure. Spencer is surprised to see the similarities between herself and Olivia when they first meet.
Spencer first tries to find Olivia when she is excluded from her grandmother's will. Her sister Melissa speculates that she might be adopted, for the phrasing in their Nana's will was: "I leave two million-dollars to each of my natural-born grandchildren. Spencer runs the theory by her classmate Andrew Campbell, who tells Spencer about a site called I Love U. It is a forum for people to find and contact their biological parents. Out of curiosity, Spencer looks at the site and puts in her details. Spencer soon receives a message from a woman named Olivia Caldwell. Olivia explains that she gave her daughter up for adoption right when Spencer was born and asks the girl to meet with her.
When she secretly visits Olivia in New York, Spencer is surprised by how much they look alike. She feels that it explains why she has dirty blonde hair and green eyes while the rest of her family has blue eyes and both her mother and sister has ash-blonde hair. Olivia hesitates when Spencer pleas to move in with her, but she quickly offers up a realtor by the name of Michael Hutchins. At the end of their day together, the woman accidentally leaves behind a portfolio with Michael's information and is gone before Spencer can alert her.
Unknown to Spencer, her "real mother" is also a scam artist. Olivia was counting on Spencer to read the false information in the portfolio she "accidentally" forgot. Spencer discovers a trust fund for college with her name on it on her dad's computer. She contacts Michael, uses that money to pay for an apartment near her mother's place in Manhattan, and feels elated to be able to leave her cold family behind. When she tries to visit Olivia again, she can't find her. Deciding to scope out her new apartment, she orders a taxi to take her to the building. However, the address of the apartment building does not exist. When Spencer tries to call Michael, she realizes the number is disconnected. She then goes to Olivia's building and asks to speak with her, only to be told that no one by that name lives in that building.
In "Heartless", the true story behind Olivia Caldwell is revealed. After confessing the loss of her trust fund to her parents, they decide to tell Spencer how she was born: Olivia did indeed give birth to her, but she was only a surrogate. Veronica Hastings is still Spencer's true mother because it is her egg that Olivia was carrying. Veronica was warned by her doctor that another pregnancy was dangerous to her health, but she and husband Peter desperately wanted another child. They met with Olivia, who was all too willing to carry their second child for them. However, Olivia became more demanding and manipulative as the pregnancy went on and threatened to run away with the baby to Canada if she didn't receive enough money. When Spencer was born, they cut off all contact with Olivia and did not want to tell their daughter about the deceitful, money-hungry surrogate.