Dr Robert Murphie, 52, known as Robbie, is believed to have worked as a GP in Stranraer.
His bike collided with a Land Rover near Creetown, five miles east of Newton Stewart, at about 12:00 on Saturday.
Two people in the Land Rover suffered shock and bruising. Police Scotland said inquiries were continuing.
A motorbike rider killed in a crash on the A75 Gretna to Stranraer road in Dumfries and Galloway has been named.