This study tested the preliminary effectiveness of a health belief and text messaging intervention for parents of five- to eight-year-old children to determine whether health beliefs and influenza vaccine receipt differ when compared to a text messaging control group. Children are almost four times more likely to be infected with influenza than adults (Belshe Piedra, & Block, 2009), shed the greatest quantities of influenza virus, and have been recognized as vectors for spread of disease (Neuzil, Mellen, Wright, Mitchel, Jr., & Griffin, 2002b). The influenza immunization rate for school-age children is less than 56% (Centers for Disease Control and Prevention [CDC], 2014). Reasons for the low vaccination rate include parents’ misperceptions of influenza disease and vaccinations (Bhat-Schelbert et al., 2012; Taylor et al., 2002). There are few theory-based interventions for increasing influenza vaccination rates of school-age children; however, promising results have been found when using the constructs of the health belief model (HBM) (Chen et al., 2011; Coe, Gatewood, Moczygemba, Goode, & Beckner, 2012). Mobile technology using Short Message Service (SMS) text messaging may increase vaccination rates to a greater extent than traditional vaccine reminders (Daley et al., 2002; Grajalva, 2006). Prior to starting this study, only one randomized controlled trial testing text messaging to increase children’s influenza vaccination rates was found (Stockwell et al., 2012). In this study, text messaging was effective in promoting behavioral changes leading to a 4% increase in influenza vaccination (27.1% vs. 22.8%, RR = 1.19, p < .001). This study was a randomized controlled trial using a two-group pre- and posttest experimental design. This study found that a theory-based intervention (SayNo2Flu) guided by the HBM and combined with the use of mobile technology (SMS text messaging) did change parents’ influenza vaccination perceptions. It had an overall increase of 38.1% in Influenza vaccination rates in the intervention group (OR: 4.46, 95% CL, 1.705-11.706, p < .001). These results offer some insight into the use of theory-based preventative interventions for parents of young school-age children.