The 45-minute service was conducted at the Chapel Royal by Justin Welby. the Archbishop of Canterbury, and also was attended by Prince Charles and the Duchess of Cornwall, the Daily Mail reported.
Queen Elizabeth and Prince William did not attend, the newspaper reported.
As part of the ceremony, holy water from the River Jordan was poured on Markle’s head, the Daily Mail reported.
After her baptism, Markle was confirmed, which means she will be able to receive Holy Communion when she marries Prince Harry on May 19, the Daily Mail reported.
Markle, 36, attended a Roman Catholic high school but was brought up Protestant, CNN reported. She did not need to convert in order to marry the prince, but she announced when she became engaged that she would.