Meghan chose a pale-colored dress by fashion label Goat and a Philip Treacy hat for the occasion. Royal watchers quickly noticed that Meghan also chose to wear pantyhose to her first post-wedding official appearance.
She was seen warmly laughing with her new in-laws, Prince Charles and Camilla, the Duchess of Cornwall.
The garden party is an early birthday celebration for Charles, who will turn 70 in November, and his patronage of hundreds of charities.
Charles, who has no daughters of his own, met Meghan at the quire of St. George's Chapel and escorted her to the altar, where Harry stood waiting.
Charles, first in line to the British throne, was also seen very publicly welcoming Meghan's mother, Doria Ragland, into the family on Saturday. He appeared to hold his hand out to Ragland at the wedding service and also walked her down the chapel's steps after the service.
Even though they got back to work today, Meghan and Harry will take a honeymoon before resuming a busy schedule of engagements for the rest of the year.
Neither the timing nor the details of the honeymoon have been released by Kensington Palace.