BACKGROUND: Asthma self-management education empowers patients to manage their condition effectively. However, evidence on its impact in Ethiopia remains limited. This study evaluated the effect of asthma education on asthma control and self-management knowledge among adult asthma patients in Ethiopia. METHODS: A quasi-experimental design was employed, with a total of 204 participants, comprising 102 individuals in the intervention group and 102 in the control group at baseline. After accounting for follow-up losses (20.6% in the intervention group and 23.5% in the control group), 81 participants from the intervention group and 78 from the control group were retained six months after the completion of the education (post-intervention). Pre- and post-intervention assessments were conducted using validated questionnaires to measure asthma control levels and self-management knowledge. The intervention group received a structured, small-group asthma education program comprising three sessions over six months. The intervention's effect was analyzed using linear regression models for difference-in-differences and interaction effects, while heterogeneity analysis was performed using a generalized linear model. RESULTS: 10% of the intervention group and 7.8% of the control group reported prior asthma management education, most of which (60%) was over a decade ago. Asthma control levels significantly improved in the intervention group, with a 19.4% increase compared to 0.6% in the control group. The overall increase in the intervention group was 18.8% higher than in the control group (P = 0.03). Similarly, self-management knowledge improved markedly in the intervention group, with a 24.3% increase compared to 0.7% in the control group. The intervention group demonstrated a 23.6% overall improvement relative to the control group (P = 0.000).Participants in the intervention group were six times more likely to achieve well-controlled asthma and 13 times more likely to exhibit good self-management knowledge compared to the comparison group (p <
0.01). The intervention's impact was consistent across subgroups, with no significant variations by socio-demographic and asthma related factors. CONCLUSIONS: Asthma self-management education interventions significantly enhance asthma management knowledge and control levels. This study highlights the need to implement and expand asthma education programs during patient follow-ups to empower patients, to reduce medical costs, unscheduled hospital visits, emergency department visits, and premature mortality. TRIAL REGISTRATION: Registered retrospectively with TRN PACTR202407741896902.