England is being overtaken by other leading nations because progress on literacy has stalled, says chief schools inspector Sir Michael Wilshaw.
Reading standards have not improved since 2005, he told BBC Two's Newsnight.
Speaking ahead of a speech on Thursday, in which he will call for targets for 11-year-olds to be raised, he said: "Our standards should be higher."
Teaching unions say big improvements have been made in the past two decades.
They have accused Ofsted and the government of "playing fast and loose with international data".
Sir Michael, who took over the chief inspector's role in January, told Newsnight: "Standards in literacy and reading went up between 1995 and 2005.
Literacy progress has stalled according to Chief Inspector of Schools.