This longitudinal study investigated friendship homophily (i.e., the preference for intra-ethnic over inter-ethnic friends) among immigrant adolescents in Israel and Germany. Based on acculturation theories and known differences between Israel and Germany in the establishment of Russian-speaking immigrant communities in these countries, it was hypothesized that levels and rates of change in friendship homophily would differ. Associations between context- and acculturation-related variables and levels and rates of change in adolescent friendship homophily were also tested. The sample consisted of 877 Russian Jewish and 358 ethnic German Diaspora migrant adolescents (i.e., migrants returning to the country of their ancestors from the former Soviet Union). Results confirmed higher levels and a less pronounced decrease of friendship homophily in Israel as compared to Germany. Especially acculturation-related variables were found to be best at predicting intercept and slope of friendship homophily. Findings also showed that differences in levels and rates of change in adolescent friendship homophily between both countries could be explained by language use; thus, using the new host language more often appeared to be a crucial variable for lower levels of friendship homophily. Overall, results suggest very similar adaptation processes toward lower friendship homophily in the two countries but at a different pace over time.