Given prior research indicating that teachers can learn through their social network interactions with colleagues, it is important to understand more about the choices teachers make about whom to go to for advice. In this study, we investigated the degree to which middle school mathematics teachers change from whom they seek advice when confronting new teaching standards and external accountability pressures (e.g., standardized tests). We found that colleagues' ability to improve student achievement was significantly related to advice seeking. In particular, teachers were more likely to seek new advice from colleagues who were better at improving student achievement. In contrast, relative differences in other types of expertise were not associated with advice seeking.