Growth faltering and nutritional deficiencies continue to be highly prevalent in infants and young children (IYC) living in low- and middle-income (LAMI) countries. There is increasing recognition that feeding behaviors and styles, particularly responsive feeding (RF), could influence acceptance of food and dietary intake and thus the growth of IYC. This paper presents the evolution of RF research and the strength of the evidence for RF on child undernutrition in LAMI countries. Multiple approaches were used to identify studies, including keyword searches in many databases, hand searches of retrieved articles, and consultation with experts in the field. Articles were included if they contained a RF exposure and child undernutrition outcome. In total, we identified 21 studies: 15 on child growth, 4 on dietary intake, 3 on disease, and 8 on eating behaviors. Most studies were conducted among children <36 mo of age and were published in the last 10 y. Cross-study comparisons were difficult due to multiple definitions of RF. One-half of the studies were observational with cross-sectional designs and few interventions were designed to isolate the effect of RF on child undernutrition. Overall, few studies have demonstrated a positive association between RF and child undernutrition, although there is promising evidence that positive caregiver verbalizations during feeding increase child acceptance of food. Recommendations for future research include consensus on the definition and measurement of RF, longitudinal studies that begin early in infancy, and randomized controlled trials that isolate the effect of RF on child undernutrition.