This paper examines the existence of social interactions in malaria preventive behaviors in Sub-Saharan Africa, that is, whether an individual's social environment has an influence on the individual's preventive behaviors. We focus on the two population groups which are the most vulnerable to malaria (children under 5?years and pregnant women) and on two preventive behaviors (sleeping under a bednet and taking intermittent preventive treatment during pregnancy). We define the social environment of the individual as people living in the same region. To detect social interactions, we calculate the size of the social multiplier by comparing the effects of an exogenous variable at individual and regional levels. Our data come from 92 surveys for 29 Sub-Saharan countries between 1999 and 2012, and they cover approximately 660,000 children and 95,000 women. Our results indicate that there are social interactions in malaria preventive behaviors in the form of social multipliers effects of women's education and household wealth. The long-run effects of these characteristics on preventive behaviors at the regional level are larger than those apparent at the individual level. Copyright © 2014 John Wiley & Sons, Ltd.