The Scottish Conservative leader said new research shows there are now 165 secondary schools in Scotland where pupils take six subjects or less in S4 - up from 46 in 2013 when the controversial curriculum for excellence was introduced.
In contrast, she said, the number of schools where pupils take seven or more subjects in their fourth year has almost halved from 308 to 182 - a drop of more than 40 per cent.
Raising the issue at First Minister's Questions in Holyrood today, she said that it was the most deprived pupils in Scotland who were being hardest hit by a subject choice squeeze, as they were more likely to leave school at the end of fourth year.
However Nicola Sturgeon said it was not simply a matter of the qualifications pupils take in S4 and accused Ms Davidson of "talking down" Scottish education.
"What matters are the qualifications young people leave school with, that they take over the entirety of the senior phase of education," she said.
"In 2009 22 per cent left of young people left school with five Highers or more, that is now more than 30 per cent of pupils and we're seeing the attainment gap narrow - the evidence does not bear out Ruth Davidson's analysis."
Ms Davidson's statistics came from Freedom of Information requests her party had submitted to every Scottish local authority, and she said they had put the results to Professor Jim Scott, honorary professor of education at Dundee University, who has examined the issue of subject choice in detail.
She said: "He said this data confirms that since the introduction of curriculum for excellence, just over 200 schools have declines or significant declines in the number of entries for SQA qualifications, and just over 50 demonstrate an increase."
And referencing the dismissal of her concerns last week by Deputy First Minister John Swinney, she added: "Does the First Minister accept that or is it part of a 'moanfest' too?"
"No matter how much Ruth Davidson wants to talk down the performance of Scottish education the facts of the matter are proving her wrong."
But Nicola Sturgeon hit back, and said: "Ruth Davidson has a bit of a cheek talking about numbers of teachers in our schools when she's the leader of the austerity party in Scotland and the leader of the party that would give tax cuts to the richest and take money out of our education system. We'll get on with the job of improving education and leave Ruth Davidson to get on with defending whatever latest Tory ends up imposing austerity on Scotland."
After FMQs Ms Davidson said: “If we’re going to improve education in this country we need to accept the evidence. That evidence shows a child in S4 is, on average, taking fewer subjects than they would have done just a few years ago. But this exchange again proved this SNP government is simply unwilling to act."