Lynsey Cargill, 35, suffered head, pelvic and lower limb injuries after her MZ motorcycle collided with a silver Ford Focus on the B954 Meigle to Dundee road south of Auchterhouse, near Dundee, on Thursday afternoon.
She was rushed to Ninewells Hospital in Dundee by an ambulance under police escort at around 4.10pm on Thursday.
Ms Cargill, of Johnshaven, Aberdeenshire, was treated in the hospital's intensive care unit but died late on Friday night.
It is understood she is survived by her partner, Greig Martin, and two children.
Paying tribute on Facebook, Mr Martin wrote: "This has to be one of the most devastating days of my life! My girl has passed away, I will miss you and love you till the day I die!
"I love you so much babe. Sleep tight, the angels are with you now."
Friends described her as a "beautiful, caring mum". Pat McLemon said: "One of the most beautiful people I have met. A lovely, vibrant, fun loving, caring mum. Totally gutted at this news, she will be so sadly missed."
Paula Beveridge added: "So very sad and hard to believe we won't see your beautiful smile again. Sleep tight."
The driver and passenger in the Ford Focus were not injured in the accident.
A spokesman for Police Scotland's Tayside Division said they were still trying to trace witnesses and he appealed for anyone who saw the collision to contact them.