1.IntroductionAdequate nutrition throughout infancy is vital for a child's optimal growth and development later in life [1]. The first two years are critical for physical and cognitive development, yet infants are vulnerable to developmental insults caused by inadequate nutrition and diseases [2]. Optimal complementary feeding practice entails fulfilling dietary diversity, meal frequency, early breastfeeding initiation, exclusive breastfeeding up to six months, and continued breastfeeding until the age of two [3,4]. At six months, an infant's energy and nutrient demand increases. Complementary feeding should be timely initiated, nutritionally adequate, and diverse to meet the child’s growing needs while continuing breastfeeding [5,6]. However, many infants and children do not receive adequate or appropriate feeding. Globally, only 44% of infants are exclusively breastfed for six months, 29.4% receive the minimum dietary diversity, and 52.2% receive the minimum required meal frequency [7]. In Ethiopia, only 59% of children aged 0-6 months were exclusively breastfed, and just 8% of infants aged 6–23 months received complementary foods while continuing breastfeeding. The 2019 Ethiopian Demographic and Health Survey (EDHS) reported minimum dietary diversity (MDD) at 14%, minimum meal frequency (MMF) at 55%, and minimum acceptable diet (MAD) at 11% [8,9]. A study conducted in the Somali regional state of Ethiopia revealed that 49.40% had optimal complementary feeding practices, with 57% initiating complementary feeding between 6–8 months, 52% achieving minimal meal frequency, and 45% attaining dietary diversity [10]. Similarly, a study conducted in the Jimma Zone of West Ethiopia found the overall proportion of optimal complementary feeding practices (OCFP) was 9.40% [11]. Several factors influence optimal breastfeeding and complementary feeding, including maternal knowledge gaps, perceived breast milk insufficiency, excessive workload, limited partner support, and food price inflation [12,13]. Childhood malnutrition remains a pressing issue in low- and middle-income countries, driven by inadequate nutrition and poor feeding practices in infancy [14]. Recognizing the importance of adequate and appropriate nutrition for child health and survival, the Ethiopian government implements health extension programs at the household and community level to improve optimal complementary feeding for children aged 6–23 months [15]. Despite child health being a priority under Ethiopia’s Health care development program [16], the national prevalence of appropriate complementary feeding practices among children aged 6–23 months was extremely low and is below international standards. There was evidence of gaps in optimal complementary feeding practices, and related factors are crucial for prioritizing, designing, and implementing intervention programs to reduce childhood undernutrition. Thus, this study aimed to assess optimal complementary feeding practices and associated factors among children aged 6–23 months in the Konzo Zone, South Ethiopia. 2.Materials and methods 2.1.Study settings and target population A community-based cross-sectional study was undertaken among 337 mothers who had children aged 6-23 months in Konso Zone, Southern Ethiopia, from May 10 to June 30, 2024. In this zone there are 3 districts, which consist of 3-5 health posts and 3-8 Kebeles. The Zone is characterized by rugged and rocky highlands cut by deep valleys. The altitude of the area is between 501 and 2000 meters above sea level, and the main agro-ecological divisions of Konso are 70% lowland and 30% tropical midland [17]. 2.2.Sample size determination and procedures The sample size was determined by using the single population proportion estimation formula. To calculate the actual sample size, a 30% proportion from a previous related study on optimal complementary feeding practice [18], 95% confidence level, 5% margin of error, and a 10% non-response rate were considered. The final sample size comprised 354 children aged 6 to 23 months paired with their mothers. Two districts were selected randomly from a total of 3 districts in the Konso Zone, South Ethiopia. In the case of Ethiopia, at least one health post was built for one to two kebeles for the provision of primary health care. From each district, one kebele that had a nearby health post was selected purposively. Then a census was conducted in two kebeles who had nearby health posts (the lowest administrative level in the case of Ethiopia) to register eligible households who had children aged 6-23 months. After getting the number of mothers who had children 6-23 months of age from all selected kebeles. The number of children assigned is based on the proportion of the size of the eligible population at all levels. Finally, the required number of mothers who had children in each kebele was selected randomly for interview. 2.3.Data collection tools and measurement A structured and pretested questionnaire was used to collect data on socio-demographic characteristics [19], dietary practices, and related characteristics. Data on dietary diversity and meal frequency data were collected by using a 24-hour recall method [20]. Mothers were asked to recall all food items given to their children in the past 24 hours before the day of the survey. According to the WHO 2021 guidelines, minimum dietary diversity for children 6-23 months was collected by using eight food groups: (1) grains, roots, or tubers; (2) legumes and nuts; (3) vitamin A-rich FV; (4) other fruits or vegetables; (5) flesh foods (meat, poultry, fish, organ meat); (6) eggs; (7) dairy products (milk, yogurt, cheese); and (8) breast milk [6]. In addition, the household food security was collected using the Household Food Insecurity Access Scale (HFIAS) to measure the degree of food security level in the past 30 days [21].Exchange of food items grown on their own...