After perestroika Russia became an attractive country for migrants, and many migrants with Russian roots returned to the motherland. They came with schoolchildren, which, according to the Federal Law “On education in the Russian Federation” have a right to general education together with the Russian citizens. But often in practice the educational achievements of these children are hindered by racism, intolerance, bad knowledge of the Russian language and other factors. Nonetheless, the results of empirical studies show that children of migrants demonstrate good academic progress, at least equal to the local students. The immigrant paradox hypothesis states that migrants are optimistic; they think and believe that in the recipient country they can fulfill their dreams and improve their living conditions. This optimism rubs off from parents to children, and as a result they study well in schools and their academic grades are high. But in the literature on academic progress there is no theory about influence of optimism on grades. In the psychological approach on academic progress recent empirical results especially stressed the role of assertiveness “grit”, that is, persistence and passion for long-term goals. Therefore, this article explores the influence of assertiveness on academic progress; mostly  comparing assertiveness of migrant children and native children. Based on  data gathered in the Yaroslavl region, and using descriptive statistics, tests of means and regression analysis the evidence suggests that children of migrants from the Caucasus have a higher level of assertiveness than the native children, which can explain their academic progress.