This paper explores the differential drivers behind the total factor productivity growth using a data set of 18 countries during the period of 1980-2007. We find that foreign education embodied human capital as a channel of knowledge spillovers has a significant effect on the growth of total factor productivity, but not direct. According to our study, the effect of R&D spillovers of foreign educated human capital on the TFP is greater for countries with higher accumulated gross domestic R&D, foreign direct investment and human capital. And the effect of knowlegde spillovers through foreign studying differs due to R&D stock lags of host countries where students study in. However, there is no significant differing effect for technology spillovers through trade. This paper contributes to the previous studies, for the first time, by revealing differential effects of R&D spillovers through foreign studying on total factor productivity.