Environmental education is considered an appropriate intervention for creating awareness of, and an understanding of the challenges of environmental degradation. The introduction of EE into the Nigerian school curricular creates a challenge of how to teach it. A majority of the teachers still employ the old, traditional “chalk and talk” method. This study experimented with two modes of participatory strategies, the full and quasi participatory modes in teaching secondary school students in Nigeria some EE concepts. Three hundred and sixty students were randomly selected and assigned to the three treatment groups. Five hypotheses were tested at P<.05 and data was collected using a test instrument measuring students’ understanding of the EE concepts taught. Findings from the study indicate that generally students taught using the participatory modes performed better than their counterparts in the conventional lecture group. However, between the two participatory modes examined, it was noted that students in the quasi participatory mode performed better than their colleagues in the full participatory group. An explanation of this could be that the quasi mode offers the learners a unique opportunity to work together in a more flexible way, to read, accept and internalize the basic environmental concepts. The implications of the findings for classroom practice were discussed in the paper.