Background: Nutrition in infancy and early childhood is a critical determinant of health outcomes and productivity of the individual throughout his/her life years. Thus, World Health Organization and United Nations Children’s Fund recommend initiation of complementary foods at 6 months to ensure optimal child growth and development. In Ethiopia, compliance with infant and young child feeding recommendations is low despite its adoption of different international policies and guidelines. Thus, the aim of this study was to assess the magnitude and associated factors of early initiation of complementary feeding among infants in Hawassa City, Southern Ethiopia, 2021. Methods: A community-based cross-sectional study was conducted in Hawassa City, in January 2021. A systematic random sampling technique was applied to recruit 543 mothers who had infants aged 6 to 12 months. A structured and interviewer-administered questionnaire was used to collect data. by six. A multivariable logistic regression analysis was applied to identify factors associated with the early initiation of complementary feeding. Adjusted odds ratio with corresponding 95% confidence interval was calculated to show the strength of association. Result: A total of 543 mothers/caregivers of infants were interviewed face to face, giving a response rate of 97%. Approximately 38% of mothers initiated complementary foods before six months of age. After adjusting for confounders, maternal employment status [AOR (95%CI): 4.72 (2.84, 7.87)] and postnatal care checkup [AOR (95%CI): 1.92 (1.24, 2.97)] were significantly associated with early initiation of complementary feeding. Conclusion: A high proportion of mothers initiated complementary feeding before six months of infant's age. Postnatal care checkup and mother’s occupational status were significantly associated with early initiation of complementary feeding. Thus, increasing the coverage of postnatal care utilization and creating mother-friendly workplaces for breastfeeding mothers is of paramount importance to realize appropriate complementary feeding practices.