Headteachers spent more than £132 million last year to close the so-called attainment gap between poorer and more affluent pupils, according to figures published today.
Money from the Pupil Equity Fund (PEF) is paid directly to heads from the Scottish government to help boost the learning among disadvantaged pupils.
During 2018-19, teachers spent 78 per cent of the total available, with the remaining cash being carried forward into the following year.
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In comparison, government analysis shows that 60 per cent of the funding available in 2017-18 was spent by headteachers.
Education secretary John Swinney said that the increase in spending of the available money showed it was working.
He added: "Closing the attainment gap will take time but we also know that what we are doing is having a tangible effect.
"The increase in Pupil Equity Funding investment by headteachers shows that our measures to empower teachers are working.
"Too often we hear the accusation that Scottish education lacks creativity and innovation. PEF proves that argument entirely wrong."
PEF was introduced in the 2017-18 academic year, with the Scottish government investing more than £242 million so far.
This is part of a wider strategy to raise attainment in the most deprived communities.
In a report published earlier this year, 88 per cent of headteachers said they had seen a closing of the attainment gap and 95 per cent said they expected to see improvements in the next five years.
Scottish Labour education spokesman Iain Gray said more of the money should have been spent in the past year.
He said: "This is not a new programme, yet even after two years it is not working as effectively as it should, with over a fifth of funds available not being spent.
"The SNP government management of the scheme must be clearer and more transparent."
Mr Gray added: "Our schools face years of budget cuts and cuts to teacher numbers while the attainment gap remains stubbornly in place, yet vital money is not being fully deployed.
"If we are to close Scotland's attainment gap, the government must examine the effectiveness of the PEF programme at a national level."
Scottish Liberal Democrat education spokeswoman Beatrice Wishart said PEF should not be used to "patch up gaps in the core teaching budget", adding that certainty around its future would help in future planning.
She said: "The problem is that PEF still isn't a permanent feature of Scottish education.
"Its year-to-year existence doesn't offer teachers and schools the certainty they need to make investments for children for the long term.
"Making it permanent would help ensure this funding is fully used."