Using integrated data from the 2006 and 2016 censuses, this study examines persistent overqualification over time among immigrants and non-immigrants. More specifically, the study examines the link between various characteristics associated with immigration and the probability of overqualification in both 2006 and 2016. In the study, overqualification is defined as a situation in which university degree holders (bachelor's degree or higher) hold jobs that require no more than a high school education. (1) Among workers aged 25 to 49 with a university degree in 2006, 20% experienced overqualification at least once in 2006 or in 2016. However, 5% were persistently overqualified (i.e., they were overqualified in both 2006 and 2016); (2) The proportion of workers who were overqualified in both 2006 and 2016 was nearly 10% among immigrants and 4% among non-immigrants; (3) Among immigrants, the location of study was an important factor in the risk of overqualification; 14% of immigrants who studied outside Canada experienced overqualification in both 2006 and 2016, compared with 4% of those who studied in Canada; (4) Immigrants who graduated in North America, Oceania, and Western and Northern Europe differed little from Canadian graduates in terms of overqualification, while graduates from Southern and Southeast Asia were more likely to be overqualified in both 2006 and 2016; and (5) Recent and older immigrants were particularly at risk of persistent overqualification. Among immigrants aged 40 and over who arrived in Canada in the five years prior to the 2006 Census and who had a university degree, nearly 1 in 5 was overqualified in both 2006 and 2016.