The purpose of this study was to examine the effects of integrating Interactive Whiteboard (IWB) technology on middle school mathematics achievement in an urban school. Propensity score matching was used to create a comparable control group in order to isolate the effects of IWB technology on mathematics achievement. An initial experimental group (n = 716) of ethnically diverse urban students receiving IWB instruction was matched to a control population (n = 856) based on propensity scores generated from demographic and ability data. Student achievement data were analyzed with 2 × 4 ANOVA to access treatment main effects and the effects of demographic variables such as gender, ethnicity, and ability. Ethnicity was a significant moderator of the effects. Specifically, a positive effect size was observed for White students, and the achievement gap was also reduced for Hispanic students. Implications for mathematics pedagogy with an IWB are provided based on these conclusions.