Indicators are considered a key tool in assessing whether societies are progressing towards sustainability. In indicator development, the main emphasis has been on the production of new indicators. Various kinds of sustainable development indicators and indicator sets have been developed to describe and assess key trends at local, national and global level. We argue that it is at least equally important to focus on how, when and by whom indicators are actually used. In addition, the focus should be on what kinds of desirable and undesirable effects are related to the use or non-use of indicators. Here, attention is paid to the negative, unintended effects of sustainability indicators in communication processes. Starting from an earlier typology focusing on health communication, various types of negative unintended effects of sustainable development indicators are identified and discussed. Copyright © 2011 John Wiley & Sons, Ltd and ERP Environment.