This study explored environmental knowledge and behavior of 350 Nigerian youth using data from a randomly administered test. Results indicated respondents had general environmental knowledge (68%), which they accessed mainly from electronic media sources. Significant differences in their environmental knowledge were in relation to subject background, and gender, but not type of school attended. Respondents showed low participation in environmental programs; while their environmental behavior was fair, it did not reflect their level of environmental knowledge. Environmental knowledge and positive behavior can be increased through appropriate media and the introduction of environmental education in schools.