The identical eight-feet-tall granite memorials, on either side of the River Tay, will name the 59 people known to have died when the bridge collapsed during a violent storm on the evening of December 28, 1879.
The train in which they were travelling plunged into the River Tay, killing everyone on board. Some claim as many as 75 people died.
The event remains one of Britain's worst ever railway disasters, but until now there has never been a memorial to remember those who perished.
The Tay Bridge Disaster Memorial Trust (TRBMT) will unveil the first of the £35,000 memorials at Wormit Bay, in Fife, in a ceremony at 10.30am, expected to attract hundreds of people.
Around 30 descendants of the victims are also expected to attend a reception in Dundee, ahead of a second ceremony at 2.30pm at Dundee's Riverside Drive, where the second granite memorial will be unveiled.
A fireworks display will be held in the evening, funded by Network Rail.