Social adjustment to college can be challenging, and social networking sites (SNSs) may ease the process. SNSs as an adjustment tool may be particularly useful for those who have relatively limited social support in their proximal environments, such as first-generation college students. This study explored how first-generation and continuing students used Facebook and Instagram, and how their usage was related to college social adjustment. Survey data from 251 undergraduates ( M_age = 19.55; 33% first generation) showed that first-generation students engaged in less Facebook interaction with on-campus friends than continuing students. For both groups, SNS interaction with on-campus friends was related to better social adjustment. Continuing students’ Instagram interaction with family was also related to better adjustment. In contrast, first-generation students’ Instagram interaction with off-campus friends and Instagram broadcasting were both related to poor adjustment. In conclusion, the two groups used SNSs in similar manners, but the implications of SNS use for college adjustment varied by students’ first-generation status.