Despite extensive research on intergroup contact and acculturation, our understanding of how contact affects receiving society members’ preferences for acculturation orientation of immigrants over time is still relatively rudimentary. This longitudinal study examined how perceived group similarity and outgroup trust mediate the effects of cross‐group friendship on acculturation preferences (culture maintenance and culture adoption) of the receiving society. It was predicted that cross‐group friendship would affect acculturation preferences over time, and that these relationships would be partly mediated by outgroup trust and perceived group similarity. A three‐wave full longitudinal sample (N = 467 Chilean school students) was analyzed using structural equation modeling. Results confirmed that cross‐group friendship longitudinally predicted majority members’ support for the adoption of Chilean culture (via perceived group similarity) and Peruvian culture maintenance (via outgroup trust). Conceptual and practical implications are discussed.