A third of Scottish primary schools are barely half-full, according to the latest figures.
Primary schools across Scotland are barely half-full
The problem is at its worst in the Western Isles where 75% have an
occupancy rate of 60% or less.
Councils in Argyll and Bute, Glasgow, Inverclyde and Shetland reported that at least half of their schools were only 60% occupied or less.
The Accounts Commission, which produced the figures, said it was concerned at the findings.
Local authorities responsible for Dundee, East Ayrshire, Highland, Orkney, South Lanarkshire and West
Dunbartonshire all reported under-occupancy in at least 40% of their schools.
Accounts Commission chairman Alastair MacNish said: "We are concerned at the low levels of school occupancy in several areas across Scotland.
"However, we acknowledge some councils are actively attempting to resolve this problem and we look forward to seeing steady improvement in future years."
The Convention of Scottish Local Authorities' (Cosla) education convener, the Reverend Ewan Aitken, said the figures showed the "difficult decisions" which councils have to take.
He said: "Local government is continually being told we need to achieve best value in everything that we do and looking at rationalisation and catchment areas is one way of securing this.
"On such a sensitive issue, councils are always the ones left with the difficult decisions between competing priorities."
The Scottish Executive said it has an "ambitious" school refurbishment programme across Scotland.
A spokeswoman said: "It is for local authorities to determine the number and location of schools, and they are already taking falling school rolls into account when planning new building and refurbishment."