Reducing socioeconomic differences in college transfer requires understanding how and why parental education, occupational class, and family income are associated with changing colleges. Building on prior studies of traditional community college transfer, the authors explore relationships between those factors and two types of transfer among four-year college students. The results indicate that reverse transfer--the move from a four-year to a community college--is more common among students from less-educated families partly because of lower levels of academic performance during their freshman year. In contrast, students from advantaged backgrounds in terms of class and income are more likely than are others to engage in a lateral transfer--from a four-year to a four-year college--which may reflect individual preferences for changing colleges, rather than a reaction to poor academic performance. Implications for policy and practice are discussed in light of the fact that only reverse transfer is associated with lower rates of completion of bachelor's degrees. (Contains 1 figure, 3 tables and 13 notes.)