International test scores are used to proxy the quality of source country educational outcomes and explain differences in the rate of return to schooling among immigrants in Canada. The average quality of educational outcomes in an immigrant’s source country and the rate of return to schooling in the host country labor market are found to have a strong and positive association. However, in contrast to those who completed their education pre-immigration, immigrants who arrived at a young age are not influenced by this educational quality measure. Also, the results are not much affected when the source country’s GDP per capita and other nation-level characteristics are used as control variables. Together, these observations reinforce the argument that the quality of educational outcomes has explanatory power for labor market outcomes. The effects are strongest for males and for females without children.