Background: Nearly 60% of teenagers in the USA have experienced abusive online behaviour. Identifying effective programmes to address these behaviours and promote digital citizenship is a research priority to reduce the rate of occurrence and consequential harmful effects of abusive online behaviour. Purpose: To evaluate the effectiveness of a Digital Citizenship Curriculum in increasing knowledge of digital citizenship and reducing cyberbullying and online aggression among middle-schoolers in an underserved community using a free curriculum. Method: Middle-schoolers participated in pilot implementation of a Digital Citizenship Curriculum (DCC) to evaluate its effectiveness in increasing knowledge of digital citizenship and reducing cyberbullying and online aggression. Follow up interviews were conducted to explore participants' perceptions of the curriculum. Results: Participants demonstrated a statistically significant increase in their knowledge of digital citizenship with an increase of 2.96 in the mean score (p < 0.001). Paired "t"-tests by gender demonstrated a significant difference in pre-post assessment mean scores for girls (p < 0.001). Post-intervention perceptions indicate the curriculum was positively received and informative. Conclusion: Identifying cost-effective and resource-friendly programmes that support social-emotional learning and promote digital citizenship is crucial for underserved populations. Regions such as Appalachian Ohio often lack the resources to fund costly curriculum aimed at online aggression prevention. This study supports the implementation of the DCC and indicates the need for future research on the long-term effects of the curriculum on middle school participants.