Environmental assessment (EA) has long been recognized as one of Canada's most important regulatory tools for protecting the environment while meeting the public's expectations for economic growth. The value of this process resides in its ability to provide useful information to decision-makers in an efficient and effective manner. In Canada, the federal government is responsible for implementing the Canadian Environmental Assessment Act 1995, while provincial governments are responsible for administering their own EA legislation. Importantly, such a multi-tiered approach to regulation can have a major impact on the collective outcomes of the decisions being made. This paper presents the results of a constant comparison of provincial, territorial, and federal Environmental Assessment Acts to clarify the extent to which requirements vary between jurisdictions in Canada. It then discusses these results in the context of the challenges facing multijurisdictional regulation of EA in Canada. Our study also demonstrates that constant comparison is an effective method for determining the common ground between the requirements of different environmental legislation, providing a grounded starting point from which strategic discussions on co-ordination between governments might proceed.