The debate over gender differences in environmental concern is sharply divided. One set of theories expects women to be more environmentally concerned than men while another set expects the opposite to be true. This study, based on a random sample of college students at a medium-sized midwestern university, tests the impact of gender on environmental concern while controlling for class standing and family income. The sample used in the final analysis consisted of 340 white students and 25 nonwhite students. Males were found to be slightly more likely than females to express environmental concern. Theoretical refinements regarding the effects of gender are drawn from marginality theory, and the overall relevance of gender is addressed.