The Duke of Sussex turns 37 on Wednesday.
William and Kate took to their joint Instagram account to share a photo of Harry grinning, along with a simple birthday message.
"HAPPY BIRTHDAY PRINCE HARRY!" the couple wrote on their Instagram Story, adding a red balloon emoji.
The official Royal Family Instagram page, which gives updates on Queen Elizabeth II and other royals, likewise celebrated Harry's big day.
The sweet post, which included cake, balloon, and "Happy Birthday" animations, featured three photos of Harry, one of him smiling as he spoke, another of him clapping at an event with his wife, Meghan Markle, and a third of him playing with a child.
"WISHING THE DUKE OF SUSSEX A HAPPY BIRTHDAY TODAY!" the Story post read.
Clarence House, the Instagram account of Harry's father, Prince Charles, and step-mother, Camilla, Duchess of Cornwall, also posted to their Story in honor of Harry's big day. The post featured a solo shot of Harry, as well as both a throwback pic and a more recent snap of the Duke of Sussex with his father.
"HAPPY BIRTHDAY TO THE DUKE OF SUSSEX!" the post, which included a cake emoji, read.
Additionally, royal family friend David Beckham wished Harry a happy birthday on Instagram.
The birthday love comes amid reports of strife in the royal family, specifically between Harry and William, which surfaced after Harry and Meghan's exit from senior royal duties and their tell-all interview with Oprah Winfrey.
Though the brothers have seen each other in person since the start of the reported feud, Omid Scobie, a royal reporter and the co-author of Finding Freedom, a book about Harry and Meghan, told ET's Nischelle Turner that their relationship "is still very much one of distance."
"These are still two brothers who aren't in regular communication, or in much communication at all, and I think they remain on these very different paths," the author said. "They are very different men. And I think that William has certainly become someone who is really living his life for the crown, for the institution. Harry has really sort of gone completely in the opposite direction."
"They will never see eye to eye," he added, "and until both sides can acknowledge that, they will never move forward."