Margaret Jamieson, 70, from Peebles, suffered fatal injuries in the accident at about 16:40 on Monday on the A703, north of Redscarhead.
Two other people - a man and a woman - were seriously injured and were taken to the Royal Infirmary of Edinburgh.
Police have urged anyone who witnessed the crash, involving a Nissan Quashqai and a VW Caddy, to contact them.

The latest data sent back from the probe has made Nasa scientists believe that Saturn's ice-crusted moon Enceladus may now be the single best place to go to find life beyond our Earth.
So, before we get all Doctor Who, let's take a look at some top facts about the exciting moon for ET-spotters...
Enceladus is the sixth largest moon of Saturn. It is about 500 kilometres (310 miles) in diameter, making it pretty small. In comparison, the Earth is over 12,000 kilometres in diameter.
Saturn has many different types of moons, some are very small, and one - Titan - is very, very large!
Altogether, Saturn has 62 confirmed moons, 53 of which have names, and only 13 of which have diameters larger than 50 kilometres.
Enceladus is named after a giant from Greek mythology.
The name was decided by the son of the man who first discovered it, astronomer Frederick William Herschel. He spotted Enceladus all the way back in 1789, during the first use of his new telescope, which was the largest in the world at the time.
Enceladus is covered in a thick surface of ice. But it's what lies deep below this icy surface that has got scientists really excited!
It's thought a warm ocean flows below the surface, where the conditions to support life could exist.
Jets of water vapour and ice particles erupt from Enceladus' underground ocean through deep icy crevasses called tiger stripes near the moon's south pole.
These plumes have provided clues about the planets inner-workings. The Cassini spacecraft conducted a fly-through of the plumes, helping to provide the data that has led scientists to believe the planet could hold life.

Darren Grayson has stepped down from the East Sussex Healthcare NHS Trust, which runs the Conquest Hospital in St Leonards and Eastbourne District General Hospital (EDGH).
In March the Care Quality Commission said A&E waiting times were "excessive" and targets were being missed.
Campaigners have called for the resignation of the board of the trust.
Mr Grayson said: "Having been chief executive in East Sussex for five years, and having led the organisation through some significant change to improve the quality of our services for patients, I believe the time is now right to hand the baton to the next leader to continue this journey of improvement."
In its latest report in March, the CQC said it had particular concerns over outpatient records and surgical practices at the EDGH.
Liz Walke, chairwoman of the Save the DGH Campaign, said: "It's a start. Let's be clear, that it isn't just Darren Grayson. We think the board should go and, unless you have a clean sweep, no significant change will happen.
"We hope there isn't going to be a massive payout. We are hoping that he has just fallen on his sword."
Former Liberal Democrat MP for Eastbourne Stephen Lloyd said: "It's about time.
"Frankly, I called for it a good 18 months ago. He still appeared to be hanging on for grim death to the post. I just thought it was absolutely outrageous."
Police have named a woman killed in a crash between a car and van near Peebles in the Borders.
[NEXT_CONCEPT]
The Cassini probe may be about to make a dramatic end to its mission, but the information it has provided about Saturn and its moons is still throwing up plenty of fascinating facts for scientists.
[NEXT_CONCEPT]
The chief executive of two Sussex hospitals, which the health watchdog said were inadequate, has resigned.