The post praised her mother, Sarah Ferguson and included a black-and-white photo of the pair smiling together.
Eugenie’s two children, August, four, and Ernest, one, could be seen in another picture included in the post.
The young Royal described herself as a “proud mama and daughter” in the post with a caption detailing how “proud” she was to be the duchess’s daughter.
The caption read: “Happy Mother’s Day from this proud mama and daughter xxxxx
Princess Eugenie is the youngest daughter of Sarah Ferguson and Prince Andrew, the Duke and Duchess of York.
The princess and duchess have a close bond and often post photos of each other to mark special occasions on social media.
Fergie posted a celebratory message last Sunday to mark her daughter’s birthday, saying: “Wishing a wonderful birthday to my beloved daughter, @princesseugenie!
“It has been a joy to watch you grow into such an extraordinary person, full of kindness, wisdom, and strength.
“Your generosity and warmth brighten the lives of so many, and I am endlessly proud of all that you do. With all my love on your special day. X”