This study explores what motivates 19 international students to pursue a Ph.D. at a public research university in the U.S. and, more importantly, what motivates them to persist despite unsatisfying socialization. Based on value-expectancy achievement motivation theory, four motivations emerged: intrinsic interest in research, intrinsic interest in teaching, high utility of a U.S.-earned Ph.D., and high emotional and social cost of quitting. As students' educational experiences unfolded, the influence of these motivations changed over time. Findings and implications are discussed in connection with the achievement motivation theory and the literature on international student mobility. Implication for future research is also provided. (HRK / Abstract übernommen).