We hypothesize that incomplete integration into the workplace and society implies that immigrants are less likely to be union members than natives. Incomplete integration makes the usual mechanism for overcoming the collective action problem less effective. Our empirical analysis with data from the Socio‐Economic Panel confirms a unionization gap for first‐generation immigrants in Germany. Importantly, using the presence of a works council as an indicator of workplace integration and contacts with Germans as an indicator of integration into society, the analysis shows that the immigrant‐native gap in union membership is heterogeneous. The gap is smaller for immigrants working in firms with a works council and having social contacts with Germans. Our analysis also confirms that the gap is decreasing in the years since arrival in Germany.