The question of class size continues to attract the attention of educational policymakers and researchers alike. Australian politicians and their advisers, policy makers and political commentators agree that much of Australia's increased expenditure on education in the last 30 years has been 'wasted' on efforts to reduce class sizes. They conclude that funding is therefore not the problem in Australian education, arguing that extra funding has not led to improved academic results. Many scholars have found serious methodological issues with the existing reviews that make claims for the lack of educational and economic utility in reducing class sizes in schools. Significantly, the research supporting the current policy advice to both state and federal ministers of education is highly selective, and based on limited studies originating from the USA. This comprehensive review of 112 papers from 1979-2014 assesses whether these conclusions about the effect of smaller class sizes still hold. The review draws on a wider range of studies, starting with Australian research, but also includes similar education systems such as England, Canada, New Zealand and non-English speaking countries of Europe. The review assesses the different measures of class size and how they affect the results, and also whether other variables such as teaching methods are taken into account. Findings suggest that smaller class sizes in the first four years of school can have an important and lasting impact on student achievement, especially for children from culturally, linguistically and economically disenfranchised communities. This is particularly true when smaller classes are combined with appropriate teacher pedagogies suited to reduced student numbers. Suggested policy recommendations involve targeted funding for specific lessons and schools, combined with professional development of teachers. These measures may help to address the inequality of schooling and ameliorate the damage done by poverty, violence, inadequate child care and other factors to our children's learning outcomes.It would be reasonable to ask 'Why another paper on class size?' For most the issue seems to have been settled: smaller classes promote higher achievement, better attitudes, different instructional practices, and higher teacher satisfaction and morale. Technical criticisms of methodology …and less-substantiated criticisms of research …would not change the general interpretation of meta-analyses in this area (Bourke 1986, 558).Many policymakers and political commentators suggest that funding isn't the problem in Australian education. They point to the funding spent on reducing class sizes, arguing that this extra funding does not lead to better academic results.1 The original version of this paper contained references to the work of Dean Ashenden that were not accurate.Version 2 of the paper removed these references. Based on comments that followed since the original publication the discussion in the later sections of the paper has also been expanded and ...