In the last five to ten years local authorities world-wide have followed the trend in the private sector and implemented standardized environmental management systems (EMSs) in their organizations. This raises questions to the reasons for implementing an EMS and, not least, about the roles and contributions of an EMS in municipal environmental policy and management. Drawing on EMS research and experiences in several countries, this review paper aims at providing a critical overview of this new phenomenon and reflects upon the potentials and drawbacks of EMS as a tool for local authorities to use in environmental management. It is argued that an EMS would primarily be regarded as a technical management tool for analytical action that helps to plan, systematize and evaluate the environmental management tasks in an organization. From a critical-emancipatory perspective, it could also, however, be interpreted as a tool for communicative action that may enhance co-operation in the municipal organization. Used in an innovative way and being aware of the potential pitfalls, the EMS may provide information, structures and processes that could help municipal actors to (re)consider their ideologies and socio-cultural structures related to environmental management.