Children are at greater risk of malnutrition in Afghanistan than they are in many other countries. Malnutrition impairs the mental and physical growth of more than 50% of children in Afghanistan. It also exacerbates the risks of mortality by 45% in infants and children in Afghanistan. The purpose of this study was to determine the association between mothers' knowledge, attitudes, and practices regarding complementary feeding and malnutrition in children in Afghanistan. The precaution adoption process model served as a theoretical framework in this quantitative cross-sectional research study. Data analyzed were collected from 306 mothers and children at 6 randomly selected hospitals in Kabul Province. The results of logistic regression models indicated that mothers' knowledge, attitudes, and practices regarding complementary feeding were statistically significant predictors of stunting in children, Ï?2 (9, N = 306) = 45.33, p < .001; Ï?2 (9, N = 306) = 26.71, p < .01; and Ï?2 (9, N = 306) = 56.97, p < .001 respectively. The strongest predictor was mothers' practicing responsive feeding, where mothers who did not practice responsive feeding were 7.1 times more likely to have stunted children than mothers who practiced responsive feeding. Moreover, the results indicated that mothers' knowledge, attitudes, and practices of complementary feeding were statistically significant predictors of underweight in children, Ï?2 (9, N = 306) = 37.49, p < .001; Ï?2 (9, N = 306) = 41.15, p < .001; and Ï?2 (9, N = 306) = 44.64, p < .001. The implications for positive social change include reviewing nutrition policies, investing in nutrition programs, and operationalizing nutrition education and behavior change interventions for promoting appropriate complementary infant feeding practices in Afghanistan.