For people who are willing or obliged to reflect on and proactively modify their personal conduct, a plethora of self-tracking devices are now widely available. By self-tracking devices we refer to near-body gadgets and related software applications that provide measurements of the rhythms and patterns of everyday life – for example, step counts, heart rate, walking distances and sleeping patterns. By providing quantitative data about vital functions or behavioural patterns, these technologies aim at helping people to enhance their self-knowledge, to adjust their behaviour and/or to accomplish self-improvement. As such, self-tracking technologies are entering and altering the domain of the ‘therapeutic’ that emerged and was consolidated during the 20th century (see Madsen, 2014, 2015; Moskowitz, 2001). Instead of approaching self-tracking as merely an instantiation of an overarching and static ‘therapy culture’, in this chapter we study more closely the therapeutic imaginaries and functions of self-tracking in everyday life, and situate the phenomenon as part of always-emergent therapeutic assemblages.