A central theme of the literature on strategic groups is that group membership affects performance. The basic premise of strategic groups and their main interest is in fact that performance can be attributed to strategic groups and not only to the idiosyncratic character of the individual firm. The aim of this paper is therefore to characterize and synthesize studies that examined the relationship between strategic groups, considered from the economic or cognitive perspectives, and performance. We notice that these studies have often yielded conflicting results. We will focus specifically on the relationship between the positioning of the firm, the strategic group and performance, a link that has hitherto been little studied in the literature. In other words, is there for the firm an optimal positioning in relation to strategic groups in its industry? The few empirical studies focusing on this relationship, emphasizing a cognitive approach, were able to show that firms moderately differentiated with respect to their belonging strategic group are more successful.