This paper presents the results of a survey among pre-service and in-service students of pre-school education and students of environmental sciences on the acceptability of value-laden statements made by their teachers on issues of sustainable development and climate change. Fifteen statements were provided, and students had to choose among the options "acceptable statement", "unacceptable statement" and "cannot decide". The questionnaire was completed by 139 students from two universities in Slovenia. The results show that the students expect their teachers to promote the principles of sustainable development. The majority of students considered any teacher's statement that would cast doubt on the cause or the necessity to act against climate change to be unacceptable. Teacher's statements emphasising global issues that have, or could have, a direct impact on developed countries (e.g. climate change) received higher support than those global questions that more heavily impact underdeveloped or developing countries (e.g. poverty, child labour, access to natural resources). In the conclusion, it is emphasised that teachers should assist students in developing their own moral positions on complex issues such as sustainable development and climate change. Structured discussion techniques, such as a panel discussion, forum and debate, should be regularly and carefully implemented into lectures at the university level.