We present a school‐based intervention geared to foster the social integration of recently immigrated (RI) primary school children by creating repeated positive contact situations with classmates brought up in the receiving society. Coaches encouraged groups of tandems, consisting of one RI and one child brought up in Germany each, to engage in cooperative activities designed to strengthen positive self‐beliefs and perception of equal status. In a quasi‐experimental control‐group design (N = 318), we compared the 30 children (12 RI) who participated in our intervention between pre‐test and post‐test with a reference group. Self‐beliefs were measured via self‐reports, social integration via sociometric peer‐nominations. The reference group (n = 288 children) included all children who did not participate in the intervention between pre‐test and post‐test: (a) 12 children (7 RI) of a waiting control group and (b) all classmates of both the students of the intervention and the waiting control group. Post‐test self‐beliefs were more positive in children having participated in the intervention. The intervention did not affect social integration: Neither the number of classmates nominating a student nor the number of peers the respective student nominated increased. Possibly, the intervention initiated self‐reinforcing processes which support social integration over longer time periods.