The percentage of undernourished toddlers on Java Island averages 8.5 %. This number is relatively high compared to the average incidence of undernutrition in toddlers in Sumatra, 3.3%. This study uses OLS, GWR, and GWANN to explore undernutrition in toddlers data on Java Island. We use cross-validation to determine the optimum bandwidth in GWR and GWANN methods. GWANN uses a single hidden layer with several hidden neurons where the number of hidden neurons is selected based on RMSE. We use indicators RMSE, MAE, and MAPE to determine the best method for modeling data on undernourished toddlers in Java. By comparing the final results, the best method for modeling data on undernourished toddlers in Java is GWR. There is a relationship between regions on the influence factor of undernutrition. Most adjacent areas, ranging from East Java to DKI Jakarta, have the same influence factor: the percentage of skinny toddlers.