In this paper, we address several issues related to seaweed domestication from an evolutionary and ecological perspective. We briefly cover the history of human interactions with seaweed and assess the importance of pre-domestication evolutionary processes. The various steps of the trajectory from wild to domesticated seaweeds are discussed for five crop seaweeds (i.e. Saccharina japonica (kombu), Pyropia sp. (nori), Undaria pinnatifida (wakame), Gracilaria chilensis (pellilo) and Kappaphycus sp.) to evaluate their domestication status. We show that seaweed domestication resulted from long-term interactions between humans, seaweeds, and environmental factors. This interplay has deeply modified the coastal ecosystem – sometimes with very detrimental effects (pests and invasions) – but was a key element in the evolutionary process leading to domestication. We then highlight the challenges for future research on seaweed domestication and show how better integration of knowledge on ecology and genetic diversity of wild populations and on the selective pressures exerted by cultivators can promote sustainable seaweed aquaculture.