This paper presents a qualitative evaluation of seven in-service environmental education teacher training courses conducted in the Czech Republic in 2009-2011. The evaluation applied a grounded theory approach. 14 focus groups, 13 interviews and two post-programme questionnaires were used. The evaluation describes a process of managing cognitive dissonance between the participants' concepts of effective teaching and environmental education and concepts presented by the courses. The paper discusses the strategies applied by the course managers for facilitating a conflict and defensive mechanisms used by the participants. The paper also discusses the implication of this experience for future courses.