Until now, many efforts in the area of environmental education, intended to instill consciously responsible behaviour into the general public in Germany, have failed. Several of the available intervention studies aimed at improving environmental behaviour of pupils with classroom tuition were able to show positive results, but there were often shortcomings in the design of these studies. First, this article presents some of these and deduces improvements and extensions for the design of the following intervention study. The described study investigated whether the active involvement and organisation in environmental activities influences the environmental behaviour of pupils. Active participation and organisation means a protection activity, designed and carried out by pupils, with help from their teacher. The results of this quantitative investigation show that the method of participation and organisation is successful and very promising. Improvements in reported and observed actual behaviour can be proved after the intervention. However, the changes are bound to the behaviour that was thematised in the teaching. The environmental perception of the pupils did not improve. Gender and the environmental perception of the pupils had no effect on the changes.