BackgroundMental, neurological and substance use disorders are highly prevalent in Ethiopia which are known to result in substantial disability. Improving the knowledge, attitude and practice of the primary health care workers is important to reduce this problem. Hence, this study aimed at assessing knowledge, attitude, and practice towards mental illness service provision and associated factors among urban health extension professionals (UHEPs) of Addis Ababa City Administration.MethodsA cross sectional study design was used. Data was collected from 455 study participants using structured and pre-tested self-administered questionnaire and analyzed using SPSS version 20 software respectively. Multivariate logistic regression analysis was performed to identify variables which have significant association with the outcome variables. The level of significant association was determined by adjusted odds ratio (AOR) with 95% confidence interval.ResultsThis study showed that 44.0% of urban health extension professionals (UHEPs) had adequate knowledge, 93.4% did not have positive attitude and 75.2% had good practice towards mental illness. Age 30 years and above [adjusted odds ratio (AOR): 95% CI 0.55 (0.34, 0.90)], having diploma educational status [AOR 95% CI 0.49 (0.32, 0.78)], and personal history of mental illness [AOR 95% CI 0.10 (0.01, 0.89)] were found to have a negative association with knowledge. Presence of job aid (AOR 95% CI 4.30 (2.59, 7.15)) and having good knowledge (AOR 95% CI 0.52 (0.32, 0.85) were increased the practice of service provision of UHEPs.ConclusionLess than half of UHEPs had adequate knowledge, most had unfavorable attitude and about three-fourth of them had good practice. Presence of job aid and having good knowledge were increased the UHEPs practice of mental health service provision. Hence, providing refresher training to UHEPs and fully implementing the national mental health strategy as well as proper clinical supervision and support to improve behavioral change is vital.