The move comes amid concern about a lack of impartial evidence of the way the Curriculum for Excellence (CfE) - which aims to make subjects more relevant, free up teachers' time and to develop more relevant skills among pupils - has been working since its recent introduction.
The Paris-based Organisation for Economic Co-operation and Development (OECD) which is designed to help improve the economic and social well-being of people around the world, is to take on the role.
The only independent academic study into the reforms, by Stirling University, found significant variation across schools and identified teacher concerns about growing workload, a lack of time for preparation and "vague" national guidelines.
But OECD officials will look at what has been achieved under the CfE and what challenges remain, with a report due in 2015.
The curriculum has been introduced into nurseries, primary schools and secondaries over the last few years with varying degrees of success.
Michael Russell, the Education Secretary, will use his address at the Scottish Learning Festival in Glasgow today to announce the evaluation.
"We have a range of data, surveys and evidence which, combined, gives us a strong picture on progress, but we plan to do more," he said.
"We will involve all groups as well as the academic community in this process, but I believe we could also benefit from further independent and international advice.
"I have asked the OECD to undertake a thorough evaluation, reporting in 2015, providing advice on how Scotland is meeting the challenges of securing the highest standards for all our children and young people."
Larry Flanagan, general secretary of the Educational Institute of Scotland (EIS) teaching union, welcomed the move, but stressed the importance of other academic evaluations.
"While the OECD does have past experience in producing reports relating to education, the EIS would have some concerns as to the organisation's suitability to assess and validate the implementation of CfE," he said.
"Concerns have previously been raised about the use of standardised assessments as a benchmarking tool for differing education systems and about the reliability of data provided by such a process.
"The EIS has not yet been consulted on this particular suggestion, but we would be keen to highlight the breadth and experience of the research base currently available within the Scottish higher education sector."
Eileen Prior, executive director of the Scottish Parent Teacher Council, added: "Having an external eye on the curriculum as it is developing is very important and there has been concern that it was not in place," she said.
"The OECD has a very specific focus on economic development and whether education is supporting that and I would anticipate some concern that other perspectives, such as the social impact, will also be evaluated."
Mr Russell will also announce a new package of financial support for CfE to pay for classroom materials. An extra £1.4 million will be made available in 2013/14 to support the implementation of new qualifications in schools, which replace Standard Grades as part of CfE.
In August, the EIS called for a support package of up to £3m arguing that schools did not have sufficient classroom materials for the National 4 and National 5 exams - less than a year before pupils sit them.
Mr Russell said the funding would ensure that, from 2014, pupils would be able to access the most up-to-date books and materials as well as online Higher courses in science, language and business.