Women are underrepresented in many undergraduate geoscience programs. Some departments are more successful at recruiting and retaining female students than others. To understand why, we investigated potential differences between more and less successful geoscience departments in terms of social support, institutional supports, institutional barriers, perceived connection to instructors, and transformative experiences. We collected data from 2,041 undergraduate geoscience students enrolled in six geoscience departments at public, four-year institutions across the United States. We recruited two departments that were successful at graduating a high percentage of female students compared to the national average (high-success sites), two departments with a moderate percentage (medium-success sites), and two with a low percentage (low-success sites). Students at high-success sites reported greater institutional supports, greater perceived connection to instructors, and lower institutional barriers than did students at medium- and low-success sites. Nonmajors at high-success sites reported higher levels of transformative experience than nonmajors at low-success sites. No significant differences were found between medium- and low-success sites. Across all sites, female students perceived less of a connection to their instructors and endorsed a lower level of transformative experience than did male students. We did not find gender differences in terms of the other factors. We also did not find gender by site interactions, suggesting that the success of high-success sites in recruiting and retaining women was associated with supporting all students. These results suggest departments can increase effectiveness in recruiting and retaining female student by increasing institutional supports, reducing institutional barriers, connecting with students, and fostering transformative experiences. [This research was supported by the National Science Foundation Gender in Science and Engineering program.]