This article examines the soundtracks of the 1960s' British sf serials Doctor Who (1963–89), Stingray (1964–65) and Thunderbirds (1965–66). It argues that Doctor Who's soundtrack reflected and utilised compositional and technological developments that were happening in the field of electronic instrumentation in Europe to convey musically the nature of an otherworldly character whose travels take him through time and space. In contrast, Gerry Anderson's series turned to a long-established, orchestral-inspired form of music to underscore and enhance narratives dominated by fast-paced action and visuals characterised by technologically advanced mechanised craft and regular scenes of explosive, destructive spectacle. Therefore, while Doctor Who was scored to 'futuristic' and experimental sounds, the soundtracks to Stingray and Thunderbirds were more 'conservative'. Through a comparative analysis, this article argues that the 1960s saw radical and significant developments not only in television sf, but also in the efficacy of music. Doctor Who and Anderson's series decisively demonstrated the effectiveness of music and soundtrack as key incidental means to establish atmosphere, tension, emotional response and action. It is argued that each series represented a potent synergy of image and sound, emphasising the central role music could play in nascent 1960s' British sf television.