This empirical study investigated the impact of positive attitudes on personal happiness among school teaching professionals in Sri Lanka using a quantitative quasi-experimental pre-test/post-test research design. A sample of 200 teachers participated in the study and completed a Positive Attitude Scale and a happiness scale before and after a structured positive psychological intervention. The intervention was designed to strengthen psychological well-being through activities such as gratitude journaling, strengths identification, positive reframing, mindfulness-based emotional regulation, and collegial relationship-building exercises. The study addressed key research questions concerning the effectiveness of positive psychology interventions in enhancing teachers’ positive attitudes and personal happiness. Results revealed that both positive attitudes and personal happiness increased from moderate baseline levels to moderately high levels following the intervention. Correlation analysis demonstrated a strong positive relationship between positive attitudes and personal happiness at pre-test (r = .61, p < .001), indicating that teachers with more positive attitudes tended to report greater happinessPaired-samples t-tests showed statistically significant improvements in positive attitudes (t = 12.47, p < .001, d = 0.88) and personal happiness (t = 11.56, p < .001, d = 0.82), reflecting large practical effects. Furthermore, hierarchical regression analysis revealed that positive attitudes significantly predicted post-test happiness even after controlling for demographic variables, including age, gender, teaching experience, and school level. The inclusion of positive attitudes increased the explained variance in happiness outcomes to approximately 40%. These findings provide empirical support for positive psychology theory and highlight the practical value of school-based well-being interventions. The study concludes that fostering positive attitudes can significantly enhance teachers’ personal happiness, resilience, and overall psychological well-being, thereby contributing to healthier and more effective educational environments.