The interest in fishing-induced life-history evolution has been growing in the last decade, in part because of the increasing number of  studies suggesting evolutionary changes in life-history traits, and the potential ecological and economic consequences these changes  may have. Among the traits that could evolve in response to fishing, growth has lately received attention. However, critical reading of the  literature on growth evolution in fish reveals conceptual confusion about the nature of growth itself as an evolving trait, and about the different ways fishing can affect growth and size-at-age of fish, both on ecological and on evolutionary time-scales. It is important to separate the advantages of being big and the costs of growing to a large size, particularly when studying life-history evolution. In this review, we explore the selection pressures on growth and the resultant evolution of growth from a mechanistic viewpoint. We define  important concepts and outline the processes that must be accounted for before observed phenotypic changes can be ascribed to growth  evolution. When listing traits that could be traded-off with growth rate, we group the mechanisms into those affecting resource acquisition  and those governing resource allocation. We summarize potential effects of fishing on traits related to growth and discuss methods for  detecting evolution of growth. We also challenge the prevailing expectation that fishing-induced evolution should always lead to slower growth.