This study aimed to assess infant and young child feeding (IYCF) practices, child nutrition status, and their variations within ethnic groups in regions with high prevalence rates of stunting. A cross-sectional study was conducted on a sample of 150 mother-child pairs that were randomly selected within regions of high stunting rates (Njombe and Geita) in Tanzania. Socio-demographic, IYCF practices, and anthropometric data (HAZ, WAZ, and WHZ) were measured and further analysed in IBM SPPS Statistics 21. In general, major ethnic groups in the Njombe district had a higher rate of stunting (53.8% vs. 37.6%; p = 0.5) than major ethnic groups in the Bukombe district. Infants aged 0-11.9 months were more stunted than other age groups. Both had optimal IYCF practices, where 46.9% of infants initiated breast milk within 1 h after birth; minimum dietary diversity was 11.6%, and only 9.1% of children in Bukombe district had a minimum acceptable diet. The major ethnic group in Njombe had a mean HAZ of -1.85, while the major ethnic group in Bukombe had a mean HAZ of -0.91. This indicates the need for initiating and expanding multicomponent nutrition interventions based on ethnic features allied with IYCF practises and child nutrition status improvement.