Malaria represents a heavy burden for developing countries. Mosquito bed nets have been proved to be an effective means of prevention and to reduce the rate of infection at the community level. However, in many African countries, bed net adoption is not as widespread as policy indications would suggest. This study uses a 13-year panel of individuals in Tanzania (KHDS) to assess the effect of social interactions in different social groups (households and neighbourhoods) on individual adoption decisions. To disentangle the effect of social interactions from that of characteristics common across group members we use a definition of social groups that exploits different timing in household membership, and is based on geographic distance for neighbourhood membership. Under the various specifications explored, we find that social learning at the household level, on average, increases the probability of adoption by up to 30% and this effect may be even higher for more educated and wealthier people. We also find that social interactions at neighbourhood level generate incentives to not adopt bed nets; the intensity of this effect is independent of geographic distance and is homogeneous across different categories of the population.