Background: The timely introduction of complimentary foods during infancy is necessary for nutritional reasons, and to enable the transition from milk feeding to family foods. Complementary foods are defined as any solid or liquid foods with nutritional value other than breast milk, offered to breast-fed infants. In the past years, despite efforts that have been put to increase the utilization of timely initiation of complementary feeding practice in Ethiopia, by governmental and non- governmental stake holders, it is not improving yet. Objective: To assess the prevalence of timely initiation of complementary feeding and its associated factors among mothers have Children 6–24 months in Debretabor and Farta ,south Gondar zone, north west Ethiopia, 2021. Methods: A community-based comparative cross-sectional study was employed from December 1/2020 to 30/ 2020 among 1100 mothers, 550 urban and 550 rural by using multi stage sampling techniques. Data were collected using a structured interviewer administered questionnaire and entered into epi data then transferred to Statistical Package for Social Science for analysis. A bi and multi variable logistic regression analysis with 95% confidence interval carried out to determine the association between explanatory and the outcome variables. P-value of < 0.05 was considered statistically significant. Results: The prevalence of timely initiation of complementary feeding among urban and rural mothers were 69.8% with 95% CI (66%, 74%) and 51.9% with 95% CI (48%, 56%) respectively indicating that the prevalence rate was higher among urban mothers. Urban (AOR=1.39, CI; 1.02, 1.94), ANC follow up [AOR (95%CI) =0.24(0.13, 0.44)], PNC follow up (AOR=0.44, CI; 0. 27, 0.72) and governmental employee [AOR=2.82; 95% CI: (1.91, 6.1)] were factors associated with timely initiation of complementary feeding among urban mothers. Whereas in rural setting institutional delivery (AOR=2.21, CI; 1.35, 3.65), PNC follow up (AOR=0.53, CI; 0.36, 0.77) daily laborer [AOR=3.47; 95% CI :( 1.78, 6.75)] were associated with timely initiation of complementary feeding. Conclusion: The prevalence is higher in urban than rural. Mothers (governmental employee) antenatal and postnatal follow up being urban; institutional delivery and postnatal follow up in rural were associated with increased timely initiation of complementary feeding. Therefore, it is better to promote timely initiation of complementary feeding at 6 months during important contact points like antenatal care, post natal care and institutional delivery. Keywords: Complementary feeding, urban, rural, Ethiopia. List of Abbreviations and Acronyms