This article makes the case that speed has become significant, indeed central, as a social scientific category and focus of attention today. In particular, it engages with two contemporary theoretical currents that conceptualize the causes, consequences and manifestations of social speed as a fundamental feature of modernity. One key contribution is Hartmut Rosa’s interpretation of ‘social acceleration’, which is offered by him as part of a reinvigorated version of Critical Theory. Another is John Tomlinson’s (complementary but different) orientation, focusing on variant cultural settings and implications of speed. By juxtaposing and assessing these two thematizations of speed/acceleration, with other recent treatments brought in at various points, the article underlines the need to clarify and debate these modal notions as a distinctive issue for social analysis. In addition, I bring out more explicitly the ambiguous nature of speed as a descriptive and normative concern. In this respect, while there can be no denying its negative-oppressive force – both structurally and experientially – it is also necessary to attend to the more positive-enabling aspects of ‘fast’ subjectivity.