People of lower-socioeconomic position (SEP) and most racial/ethnic minorities face significant communication challenges which may negatively impact their health. Previous research has shown that these groups rely heavily on interpersonal sources to share and receive health information; however, little is known about these lay sources. The purpose of this paper is to apply the concept of a market maven to the public health sector with the aims of identifying determinants of high health information mavenism among low-SEP and racial/ethnic minority groups and to assess the information they may be sharing based on their own health beliefs. Data for this study were drawn from the baseline survey (n = 325) of a US randomized control intervention study aimed at eliciting an understanding of Internet-related challenges among lower-SEP and minority individuals. Regression models were estimated to distinguish significant determinants of health information mavenism among the sample. Similarly, bivariate and logistic multivariable models were estimated to determine the association between health information mavenism and accurate health beliefs relating to diet, physical activity and smoking. The data illustrate that having a larger social network, being female and being older were important factors associated with higher mavenism scores. Additionally being a moderate consumer of general media as well as fewer years in the US and lower language acculturation were significant predictors of higher mavenism scores. Mavens were more likely than non-mavens to maintain accurate beliefs regarding diet; however, there was no distinction between physical activity and smoking beliefs between mavens and non-mavens. These results offer a unique understanding of health information mavenism which could better leverage word-of-mouth health communication efforts among lower-SEP and minority groups in order to reduce communication inequalities. Moreover, the data indicate that health information mavens may serve as an ideal point of intervention in attempts to modify health beliefs with the goal of reducing health disparities among these populations.