Sarah Buick, 24, posted a selfie from the top of the mountain to social media at around 5am on Tuesday.
It was captioned: “Good morning from ben nevis!”
The experienced walker, from Dundee, has not been seen or heard from since.
Police said there is growing concern for her safety and have issued an appeal for help.
They said she walked to the summit from the Lower Falls area of Glen Nevis, to the south of Ben Nevis.
She may have walked to other locations after her climb to the summit or intended to return using a similar route to descend to Glen Nevis.
Ms Buick is around 5ft 3in, of slim build with long brown hair.
She was wearing a light green jacket and carrying an orange rucksack.
Inspector Nick Hough of Fort William Police Office said: “As time goes on we are becoming increasingly concerned for Sarah.
“She is an experienced walker and often makes trips alone, but it is very unlike her to be out of contact with friends and family for this length of time.
“We are appealing to anyone who may have been in the Ben Nevis or Glen Nevis area over the last 36 hours and has seen anything which may help our searches to please get in touch.”
Anyone with information can contact police on 101.