Ready-to-eat (RTE) cereal is a popular food among children. However, there are no recent data on the associations between RTE cereal consumption and dietary outcomes in the U.S. Therefore, we sought to investigate how RTE cereal was associated with nutrient and food group intakes and overall dietary quality among children aged 0.5 to 17 years using the latest data from the National Health and Nutrition Examination Survey (NHANES 2015-2016). Thirty-six percent of children reported consuming RTE cereal. RTE cereal eaters consumed the same number of calories as non-eaters but had higher intakes of total carbohydrates, total sugar, fiber, calcium, iron, magnesium, potassium, zinc, vitamin A, thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, and vitamin D, as well as lower intakes of total fat and saturated fat (p ≤ 0.0007). We also found that children who consumed RTE cereal had 29% higher total dairy intake (p < 0.0001) and 61% higher whole grain intake (p < 0.0001). Lastly, children who ate RTE cereal had higher diet quality than the children that did not eat RTE cereal, as shown by Healthy Eating Index 2015 total score (52.6 versus 47.7, p < 0.0001). Therefore, consumption of whole-grain fortified RTE cereals should be encouraged as part of healthy dietary patterns for children.