In the Philippines, there is an increasing prevalence of overnutrition in adolescents and with this comes rising vulnerability to nutrition-related diseases. The WHO stated that a healthy diet can protect individuals against all forms of malnutrition. Thus, this study centers on the association between knowledge, attitudes, and practices on healthy diet and the nutritional status of the senior high school students. A descriptive cross-sectional study design was used in this study. A questionnaire regarding KAP on healthy diet was administered. Self-reported anthropometric measurements were utilized to determine the nutritional status of the students. The KAP were scored, and the average score and weighted means were categorized accordingly. The SPSS software was used to statistically compute the relevant data. The results have shown that 63.04% of the respondents are with good knowledge, 63.60% are with high positive attitudes, and 63.00% are with high positive practices on healthy diet. An association was found between religion and knowledge. Moreover, knowledge is associated with attitudes and the attitudes with practices. However, the study also concludes that the nutritional status of the respondents is independent from their knowledge, attitudes, and practices on healthy diet. Further studies are recommended to know what directly affects the nutritional status of the students.