Background: Breastfeeding is essential for promoting infant health, particularly in the first six months of life. It serves as a critical public health strategy to improve the health of both children and mothers by reducing child morbidity and mortality while lowering societal healthcare costs. Despite its importance, teenage mothers often face distinct challenges in adhering to recommended breastfeeding practices. Targeted health messages offer a promising solution, providing personalized communication that enhances breastfeeding practices and ultimately improves infant health outcomes. Method: A randomized control trial was employed across baseline, intervention, and post-intervention phases. The study targeted teenage mothers with infants less than six months who were attending public hospitals in Tharaka Nithi County. Data collection tools used were structured questionnaires and focus group discussions (FGDs). Quantitative data was analyzed using the statistical package of social sciences (SPSS) version [29]. Descriptive and inferential statistics were used, ANOVA, Chi square and regression analysis. Qualitative data was analyzed thematically and the results presented in narratives, figures, and tables to ensure clarity and comprehensiveness. Results: The study revealed significant improvements in knowledge on breastfeeding practices among teenage mothers following the targeted messages intervention. Knowledge scores increased significantly (p < 0.05) across domains related to early initiation, frequency of breastfeeding and exclusive breastfeeding. On baseline knowledge levels had a one-way Anova of F=72.34 (high) and p=000002 (small) which affirmed that intervention led to a statistically significant difference in breastfeeding practices across test faces. The results were supported by regression results that showed pretest scores to be positive predictors of posttest scores. Conclusion: Targeted health messages significantly improved Knowledge, attitudes and