This research identifies social crowding as a situational factor that influences consumer responses to personalization. Across a series of studies, I show that social crowding leads to less favorable responses to personalization because people are less willing to express themselves in crowds. I also demonstrate that social crowding negatively impacts personalization only when consumers have lower interpersonal trust or when others in the crowds are out-group members. This research identifies social crowding as a situational factor that influences consumer responses to personalization. Across a series of studies, I show that social crowding leads to less favorable responses to personalization because people are less willing to express themselves in crowds. I also demonstrate that social crowding negatively impacts personalization only when consumers have lower interpersonal trust or when others in the crowds are out-group members.