This perspective summarizes our knowledge of the freshwater habitat of Atlantic salmon (Salmo salar). The article is organized by life stage and identifies areas where more research is needed. For example, little is known of the kelt and presmolt life stages despite their importance in stock maintenance. We also believe that further investigation is required to assess the relevance of variables currently used to characterize habitat and that more attention should be focussed on adult and embryo-larva habitat requirements. We also discuss the fact that the majority of research is directed at habitat at the micro (i.e., immediate area around the fish) and macro scales (area of the geomorphological unit), while the influence of habitat at higher spatial scales should also be considered.