Treatment outcomes of tuberculosis in children are rarely evaluated. Childhood tuberculosis has been a low priority for tuberculosis programs due to difficulties in diagnosis and treatment. This study evaluated childhood tuberculosis outcomes and factors associated with unsuccessful treatment outcomes in selected public hospitals in Lusaka, Zambia from 2015 to 2019. This was a cross-sectional study conducted in eight public hospitals in Lusaka. All children aged 0-14 years, treated with tuberculosis and had treatment outcomes evaluated were included. The WHO tuberculosis treatment outcomes were grouped into successful treatment outcome (cured, treatment completed) and unsuccessful treatment outcome (death, loss to follow-up, failure). Taking unsuccessful treatment outcome as the outcome variable, logistic regression models were performed. All analyses were done at a 95% confidence interval. Out of 2,531 children managed for TB from 2015 to 2019, only 1,495 (59.1%) had treatment outcomes evaluated. Out of 1,495 participants, majority were 5 to 14 years old (50.9%), males (51.1%), HIV-negative (58.7%), and had pulmonary tuberculosis (74.2%). Bacteriological tests were performed on 59.8% of children, where 21.6% had positive bacteriological results. Bacteriologically confirmed TB was higher in children over 5 years (29.5%), pulmonary TB (25.6%), and retreatment (28.6%). The majority of children (84.2%) completed treatment, while 10.7% were cured, 1.5% were lost to follow-up, 3.1% died, and 0.5% failed treatment. Overall, unsuccessful treatment outcome was 5.1% while successful treatment outcome was 94.1%. Extrapulmonary tuberculosis was associated with unsuccessful treatment outcomes (AOR 1.64; 95% CI: 1.02-2.62). The tuberculosis successful treatment outcome met the World Health Organization's threshold goal of 90%. Children with extrapulmonary tuberculosis should be targeted as a high-risk group to improve treatment outcomes. Tracking children whose treatment outcomes were not evaluated would provide more precise estimates of TB treatment outcomes.