The rocker posted a photo of his former partner on Twitter Thursday (28Apr16) and added the caption: "Remembering L'Wren on her birthday."
Jagger did something similar last year (Apr15) to mark her 51st birthday.
The fashion designer was found dead in her New York City apartment on 17 March, 2014. Reports suggest she took her own life.
"I am still struggling to understand how my lover and best friend could end her life in this tragic way," Jagger, who dated Scott for over a decade, said in a Facebook post at the time. "We spent many wonderful years together and had made a great life for ourselves... I will never forget her."
Her death prompted Jagger and his Rolling Stones bandmates to reschedule a string of dates in Australia, so he could fly back to America to help plan Scott's funeral.
He was diagnosed with acute traumatic stress disorder after his girlfriend's death, according to legal papers filed as part of an insurance dispute over the Stones' scrapped Australian and New Zealand tour.
Court documents filed for the dispute suggested the band postponed the tour because Jagger was ordered not to perform for 30 days by a doctor, who diagnosed the rocker with the stress disorder.
The Rolling Stones returned Down Under to complete the tour in November, 2014, when Jagger confessed it was good to get back on the road after months spent mourning the loss of his girlfriend.
"It was a very difficult time for me, all my family as well, it's very hard but getting back on tour... helped me a lot," he said.