Nearly half of all first‐time undergraduates take a loan to pay for college, and many students will borrow tens of thousands of dollars by the time they leave. Low‐income students and students of color borrow student loans more often and in larger amounts, yet attend less selective institutions, are more likely to drop out with debt. Among students who complete college, those with larger amounts of debt may struggle to pay back their loans or to invest in a house, family, or future education. Researchers are just beginning to untangle how the availability and use of student loans affects college access, educational attainment, and life after college, yet this topic has important implications for economic inequality and social stratification. In this article, we summarize what is known and what remains to be investigated, about the impact of student loan availability and use on college enrollment, degree completion, and postcollege outcomes.