An adequate, diverse, and nutritious diet is critical to early development. Due to a number of factors, however, access to quality food sources is limited for much of the developing world. This research study investigates the relative extents to which nutritional status and water quality are associated with (explain variance in) children’s body size on the Nyakach Plateau in rural western Kenya. Survey responses indicated widespread hunger: nearly half of the children in this sample (n=172) are in families with the highest level of acute food insecurity (FI). Family acute FI status significantly explained variance in children’s BMI-for-age z-scores (BMIZ) (R2=0.18, F=5.25, p=0.0007). Survey responses also revealed that families’ mean percent of energy consumed from protein was only a fraction of the 10 to 35 percent recommended for children (x̄=0.035, SD=0.038). This measure of family percent energy from protein significantly explained variance in children’s height-for-age z-scores (HAZ) (R2=0.07, F=8.68, p=0.0039). Water quality was operationalized in this study as possession and frequent use of a rainwater collection tank, and in the absence of a tank, as the use of water purification methods. Among extremely food insecure families who owned tanks, duration of tank water during Kenya’s dry season explained significant variance in children’s BMIZ scores (R2=0.45, F=5.25, p=0.0031). Among families without tanks, acute food insecurity status explained significant variance in children’s BMIZ scores (R2=0.47, F=10.82, p < 0.0001). This study provides justification for installation of rainwater collection tanks in communities similar to the Nyakach Plateau, especially among the most food insecure families.