During the 1970's there was considerable research interest in environmentally concerned consumers. Mirroring societal interest levels, such research waned in the 1980's. Today, this topic has regained its relevance, however. Marketers actively target these consumers and public policy makers strive to increase their numbers. In addition, research activity pertaining to these consumers has increased noticeably in recent years. Despite the increased attention to environmental concern, a viable conceptual framework for its study is still lacking. A review of past work indicates that environmental concern has been variously treated as a group of behaviours, attitudes, affect, and intentions. In order to clarify the construct and provide needed theory for its study, a framework of environmental concern is provided here. This framework is drawn from existing work on environmental concern and research pertaining to consumer involvement. The nature, outcomes, and sources for environmental concern are discussed along with marketing and public policy implications.