In the last 30 years, women experienced dramatic increases in college attendance and completion. Women now make up the majority of college attenders and completers, and their numbers continue to grow. Recent research shows that these gender differences are driven largely by changes among women in rates of college attendance. What is causing these dramatic increases in college attendance among women? Studying three distinct cohorts representing the high school graduating classes of 1972, 1982, and 1992, this article studies two possible mechanisms leading to women's changing patterns of college attendance: changing academic achievement, and changing pathways into and through college. Results show that changes in the "effects" of achievement on college attendance decisions are driving women's increasing college attendance. The expansion of higher education--particularly the route through 2-year college to 4-year college--increased opportunities for enrollment and women disproportionately took advantage of these opportunities. High-achieving women, who in the past did not attend college, are now attending and using these non-traditional paths to increase their rates of college attendance.