This paper examines the determinants and the effects of the presence of a third person in face-to-face interviews that were conducted with second-generation residents of Turkish parents and their non-migrant counterparts in six western European countries. The presence of a third person in social science interviews is assumed to influence the results of surveys in social sciences. Up to now, however, only a small number of studies have investigated the presence of a bystander in interviews with migrant descendants, its determinants, as well as its effects on other variables. We used data from the project on The Integration of the European Second Generation (TIES 2007–2008) for Austria, Belgium, France, Germany, the Netherlands, and Switzerland. The sample consisted of 5870 respondents, of whom 51% were descendants of Turkish immigrants, who had visited school in the respective country of residence. The respondents were 18–35 years old. Our results show that a much larger share of second-generation residents than of non-migrants were interviewed in the presence of a third person (33% and 21%, respectively). In addition, we found that women of Turkish descent were more likely to have been interviewed with a bystander present than men, whereas there was no gender effect among natives. These differences can only partly be explained by differences in the opportunity structures between the groups, which were mainly related to household composition. This finding may be attributable to culture-specific motivations for a bystander presence. Moreover, the effect of a third-party presence on attitudes was tested. The responses given in the presence of a bystander varied from those given in anonymity.