Three gorgeous photos of Meghen were posted on the royal family's social media accounts, along with a sweet caption that read: "Wishing The Duchess of Sussex a very Happy Birthday today!"
The first showed the Duchess with the monarch on their first joint engagement together in Chester in June 2018, with Her Majesty in a green coat and Meghan looking elegant in a Givenchy dress with a cape.
The second Prince Harry and Meghan on their tour of Africa with baby Archie in September 2019 and a third showed the couple applauding at the Endeavour Awards in 2020, one of their final royal engagements.
WATCH: Meghan Markle talks about meeting the Queen for the first time
The Sussexes now reside in Montecito, Santa Barbara, with their children, Archie, two, and two-month-old Lilibet.
Prince Harry and Meghan's daughter, who was born on 4 June at Santa Barbara Cottage Hospital, is named after her great-grandmother, the Queen, whose family nickname is Lilibet.
The couple are yet to publicly share a photo of their baby girl, who is eighth in line to the throne after her big brother Archie.
The Sussexes have been carving out a new life in the US after stepping back from royal duties in March 2020.
The Queen shared sweet photos of Meghan on her birthday
Harry has returned to the UK twice since then; for the Duke of Edinburgh's funeral in April and to unveil a statue of his late mother, Diana, Princess of Wales, at Kensington Palace with his brother, Prince William, in July.
The Duke stayed with his cousin, Princess Eugenie, and her husband, Jack Brooksbank, during his visits to the UK. Eugenie and Jack are currently residing at the Sussexes' Windsor home, Frogmore Cottage.
It's not known when Harry and Meghan might visit the UK as a family in future.
Meanwhile, the Queen is currently enjoying her annual break at her Scottish estate, Balmoral.
Make sure you never miss a ROYAL story! Sign up to our newsletter to get all of our celebrity, royal and lifestyle news delivered directly to your inbox.