Seascape genetics is the study of how spatially variable structural and environmental features influence genetic patterns of marine organisms. Seascape genetics is conceptually linked to landscape genetics and this likeness frequently allows investigators to use similar theoretical and analytical methods for both seascape genetics and landscape genetics. But, the physical and environmental attributes of the ocean and biological attributes of organisms that live in the sea, especially the large spatial scales of seascape features and the high dispersal ability of many marine organisms, differ from those of terrestrial organisms that have typified landscape genetic studies. This paper reviews notable papers in the emerging field of seascape genetics, highlighting pervasive themes and biological attributes of species and seascape features that affect spatial genetic patterns in the sea. Similarities to, and differences from, (terrestrial) landscape genetics are discussed, and future directions are recommended.