Figures showing teaching posts have been advertised up to 14 times should be a "wake-up call" for the Scottish government, according to the Liberal Democrats.
The party said it was "extremely troubling" to see some schools having to advertise jobs over and over again.
The figures were uncovered by the Scottish Lib Dems after freedom of information requests were submitted to each of Scotland's 32 local authorities.
The 26 responses show that one secondary post, for a technical education teacher at Ellon Academy in Aberdeenshire, has been advertised 14 times, with only four applications received throughout the process.
Also in Aberdeenshire, primary teacher vacancies in Banff have been advertised seven and nine times, while an Aboyne Academy chemistry teacher post was advertised six times.
On the other side of the country, a vacant primary school teaching post in East Ayrshire was advertised nine times.
Meanwhile, the figures show a teaching post in Dundee vacant since June 2017, and a post to teach Gaelic in Aberdeen being advertised seven times, with one application received.
The responses also reveal that some advertised posts have drawn no applications.
The data comes weeks after it emerged that nearly 3,000 teaching vacancies have been re-advertised in the last three years.
Scottish Liberal Democrat education spokesman Tavish Scott said: "These new figures demonstrate the pressure in schools for teachers across all subjects. Headteachers are simply unable to find the staff that they need.
"It is extremely troubling that teaching posts are being advertised over and over again. The data published by Liberal Democrats today reveal that it is now all too common for councils to advertise jobs and not receive a single reply.
"This applies to core subjects such as maths and English. This will have a huge impact on Scottish school pupils' learning.
He added: "One post has been advertised 14 times. If that is not a wake-up call for Scottish ministers I do not know what would be. The SNP government must face up to this crisis that is a reality across Scotland."
The EIS union is campaigning for a 10 per cent pay rise for teachers, and there have been warnings over the possibility of strike action if an "acceptable" pay offer is not put forward.
Mr Scott added: "The teaching profession must believe that it is valued by government. That starts with giving teachers a fair pay deal backed by ‘McCrone 2’ – an independent root-and-branch review of teachers' terms and conditions and the demands placed upon them."
The Scottish government said teacher numbers are at the highest level since 2010, with primary teachers at the highest level since 1980.
Education secretary and deputy first minister John Swinney said: "We want to keep people in the profession and to attract new entrants into teaching.
"That's why we have increased targets for recruitment into initial teacher education, created new routes to make it more practical and flexible for people to access courses and run a teacher recruitment marketing campaign.
"There are also fewer teaching vacancies across the country, including significant reductions in jobs advertised for more than three months, demonstrating the impact of our investment in attracting new talent to the profession."