ObjectiveThis paper examines the acceptance of the Advocacy Core Group (ACG) programme, a social and behaviour change intervention addressing maternal, newborn, child health and nutrition (MNCH+N) in Bauchi and Sokoto states, with an additional focus on the perceived endorsement of health behaviours by social networks as a potential factor influencing acceptance.DesignThis study used the qualitative social network analysis approach and used in-depth interviews to collect data from 36 participants across Bauchi and Sokoto states.SettingThis study was conducted in selected communities across Bauchi and Sokoto states.ParticipantsA purposive sample of 36 participants comprised of men and women aged 15–49 years who have been exposed to the ACG programme.ResultsProgramme beneficiaries actively engaged in various ACG-related activities, including health messaging delivered through religious houses, social gatherings, home visits, community meetings and the media. As a result, they reported a perceived change in behaviour regarding exclusive breast feeding, antenatal care visits, family planning and malaria prevention. Our findings indicated consistent discussions on health behaviours between programme beneficiaries and their network partners (NPs), with a perceived endorsement of these behaviours by the NPs. However, a potential negative factor emerged, whereby NPs exhibited perceived disapproval of key behaviours, which poses a threat to behaviour adoption and, consequently, the success of the ACG model.ConclusionsWhile findings suggest the successful implementation and acceptance of the model, it is important to address possible barriers and to further explore the socially determined acceptance of MNCH+N behaviours by NPs. Interventions such as the ACG model should mobilise the networks of programme participants, particularly those with decision-making power, to improve the uptake of health behaviours.