This paper analyses the use of sound in BBC Wales' Doctor Who (2005–). It argues that rather than offering a single, unified strategy for sound design, the show ‘sounds science fiction’ in multiple, over-determined ways. Firstly, it is suggested that sound functions as a marker of brand identity; this is particularly so since created science-fictional sounds lack naturalistic analogues. Indeed, the series has preserved ‘sonic stars’ from Doctor Who's earlier run (1963–89), using sound effects to affirm textual authenticity. Secondly, the paper considers how science-fictional ‘otherness’ and monstrosity are sonically constructed. It is suggested that the ‘acousmetre’ has been a crucial device. This enables sound to function as a narrative lure, withholding but promising monstrous televisuality, as well as providing SFX budgetary control. And the acousmetre plays a significant role in promotional paratexts; official trailers repeatedly feature monstrous sounds without televisually revealing the fantastic. However, Chion's definition of the acousmetre also requires some rethinking via the ‘gothic acousmetre’ which fantastically destabilizes voice–body correspondence. Finally, the paper considers how ‘ordinary’ sound frequently becomes uncanny in the series. ‘The sound of drums’, the ‘four knocks’ and voices in ‘Midnight’, have all become sonic markers of science-fictional otherness emerging through the everyday/familiar. Brand familiarity, alien otherness and uncanny oscillations between familiar/alien form the multiple, (un)earthly roles of sound in Doctor Who.