Background: The Investment Framework for a more effective HIV response has become integral to discussions on how best to respond to the HIV epidemic. The Framework calls for greater synergy and attention to factors that serve as 'critical enablers' and optimise HIV programmes. In this paper we argue for recognition of informal and indigenous community groups as 'critical enablers' of the HIV response. Methods. This qualitative study was conducted in Matobo district of the Matabeleland South province in Zimbabwe. It draws on 19 individual in-depth interviews and 9 focus group discussions conducted by local researchers in September and October 2011. Data was thematically analysed. Results: Four core themes highlight the possibilities and limitations of community groups in the HIV response: (i) Membership of indigenous community groups and group-based dialogue were found to encourage group members to engage with HIV prevention, mitigation and care efforts; (ii) local networks and partnerships between groups and NGOs were said to play an important role in accessing much needed resources to aid indigenous coping with AIDS; (iii) community strengths and resources were recognised and drawn upon in the community group response; (iv) frequent droughts, poverty and stigma served as obstacles to an effective HIV response. Conclusions: In this context, social groups, although to varying degrees and in direct or indirect ways, play a key role in the HIV response. This suggest that community groups and networks can indeed act as 'critical enablers' to the HIV response, and that efforts need to be made to facilitate the contributions of already existing indigenous responses. Local community groups are developing local and collective solutions to structural problems, often independently of external NGO or health service efforts, and begging for synergy and collaboration between local community groups and networks, the health services and other external HIV service delivery sectors.