Specialisation and delegation of policy leadership within committees is the norm rather than the exception in legislatures around the world. Yet, little research has studied the sub-groups of lawmakers who serve as policy leaders on particular bills. This article uses conceptual and methodological tools from social network analysis to investigate the groups’ composition and relational structure. It tests the proposition that limited human resources lead lawmakers from small parties to more frequently engage with a greater number of colleagues from other parties across a wider range of policy areas. This may have important relational benefits that have the potential to outweigh the structural disadvantages of small party size. The article examines whether small party lawmakers participate more, are more central and have greater potential for brokerage in policy-making networks, or if the constraints associated with small party size and/or particular ideological leanings prevent their realisation. Empirically, the analyses focus on working relationships between rapporteurs and shadow rapporteurs in the adoption of reports by standing committees of the 7th European Parliament, 2009–2014. Methodologically, a mixed methods approach is employed. The quantitative analyses show that small party size does not affect legislators’ participation in policy-making networks, but that it increases legislators’ centrality and brokerage potential. Regarding ideology, being committed to democratic participation as a good in itself has a positive association with all three outcomes, while attitudes to European integration show no effect. The qualitative data suggest that the relational benefits of belonging to a small party partially mitigate the structural disadvantages associated with it. They also indicate that policy making in the European Parliament is quite inclusive, as any systematic exclusion tends to be the result of self-marginalisation.