In this study, we investigated the factors associated with education-job mismatches among US workers by immigrant generation. We used the data from the U.S. sample of the Program for the International Assessment of Adult Competencies (PIAAC) and documented the distribution of education-job mismatches across selected independent variables. We estimated the relationship between the individual characteristics of workers and education-job mismatch using multinomial logistic regressions and found that on average, immigrant workers were more likely to be overmatched for the jobs they held in the U.S. labor market, with first-generation workers being overmatched more frequently than second-generation workers. Our results imply that some adjustments towards a merit-based system of immigration might be beneficial for integrating newcomer immigrants into the labor market.