Presley died in January after suffering cardiac arrest.
The Daisy Jones & The Six actress took to Instagram Sunday to pen a touching tribute to her late mother, along with a sweet photo of herself as a newborn cradled in her mother and father, Danny Keough's arms.
"Lucky to have had the best and most deeply loving mama I could have asked for 💕," Riley, who quietly welcomed her first child with husband, Ben Smith-Petersen in 2022, captioned the post.
The post was met with lots of love from fans and fellow celebrities alike, with one user writing, "Sending love to you! Happy Mother’s Day to you too 💖," and mother-to-be, Lindsay Lohan, leaving behind a trail of red heart emojis.
This Mother's Day marks Riley's first since Lisa Marie's tragic death in January. Lisa Marie, the only daughter of Elvis and Priscilla Presley, died on Jan. 12 after going into full cardiac arrest at her home in Calabasas, California. Her heart restarted after CPR was administered en route to West Hills Hospital in Los Angeles, but she died later that day at 54 years old.
It also marks the first since Riley's husband confirmed that he and the 33-year-old actress are parents to a little girl.
Ben made the revelation during Lisa Marie's public memorial service at Graceland in Memphis, Tennessee Back in February, after he took the podium in place of his wife to read a few words written by Riley that she dedicated to her late mother.
During the tribute, Ben read a line in which Riley spoke about being a loving mother to her child like Lisa Marie was to her and her three siblings -- the late Benjamin Keough and 14-year-old twin daughters Harper and Finley Lockwood.
"I hope I can love my daughter the way you loved me, the way you loved my brother and my sisters. Thank you for giving me strength, my heart, my empathy, my courage, my sense of humor, my manners, my temper, my wildness, my tenacity," Ben read on behalf of his wife. "I'm a product of your heart, my sisters are a product of your heart, my brother is a product of your heart."
Riley and Ben tied the knot during multiple ceremonies in 2015 after meeting on the set of Mad Max: Fury Road. February's memorial service marked the first time the couple has publicly mentioned having a child.