Improper waste management is an environmental concern. The contribution of attitude, subjective norms, and perceived behavioral control as determinants of waste management practices was verified. Diagnostic research design, proportionate stratified random sampling, survey technique, and multiple linear regression were the methods used. The data from 351 public-school learners revealed that  subjective norms and perceived behavioral control, not the attitude toward waste management significantly influence waste management practices. This result partially affirms The Theory of Planned Behavior. School leaders, teachers, learners, and future researchers may strengthen waste management practices through programs and activities that promote environmental awareness, supportive social influence, and sustainable behavior among learners.