BackgroundFrailty is a condition resulting from a decline in physiological reserves caused by an accumulation of several deficits, which progressively impairs the ability to recover from health adverse events. Following a promising feasibility study, the HomeHealth trial assessed a holistic tailored intervention for older adults with mild frailty to promote independence in their own homes, compared with usual care. We aimed to understand how goal setting worked among older people with mild frailty. MethodsThis study was a process evaluation alongside the HomeHealth randomised trial in older adults with mild frailty. The intervention was delivered at participants’ homes, either in person or by telephone or videoconferencing. We carried out semi-structured interviews with older participants who had received the intervention (between three and six appointments), on average 233 days (range 68–465) after their last appointment, purposively sampled according to age, gender, number of sessions attended, adverse events, ethnicity, Index of Multiple Deprivation, Montreal Cognitive Assessment (MoCA) and Barthel scores, research site, and HomeHealth worker. We also conducted interviews with HomeHealth workers who delivered the intervention (n=7). Interviews explored the experience and process of goal setting, benefits and challenges, perceived progress, and behaviour change maintenance after the service had finished. Ethics approval was obtained, and all participants gave informed consent. Interviews were thematically analysed. HomeHealth workers kept formal records of goals set and assessed progress towards goals (0–2 rating scale) during six monthly-sessions, which were descriptively summarised. Findings56 interviews were completed between July 15, 2022, and May 18, 2023. Study participants (n=49) had a mean age of 80 years (range 66–94), including 32 (65%) women and 17 (35%) men. Participants self-identified as White (n=42), Asian (n=3), Black (n=2), Mixed (n=1), and other ethnic (n=1) backgrounds. Findings suggested goal setting could be both a challenge and a motivator for older participants with mild frailty. Goal setting worked well when the older person could identify a clear need and set realistic goals linked to functioning, which led to a positive sense of achievement. Challenges occurred when older people were already accessing multiple resources and health services, or where the terminology of “goals” was off-putting due to work or school connotations. Average progress towards goals was 1·15/2. Most participants set goals around improving mobility (or a combination of mobility and another goal type such as socialising), and there was evidence of participants sustaining these behaviour changes after the intervention. InterpretationOlder people with mild frailty can engage well with goal setting to promote independence. The lapse between receiving the intervention and being interviewed limited recall for some participants. However, the acceptability and adherence to the intervention for older people with mild frailty, and their moderate progress towards goals, should encourage further tailored and person-centred practices to promote their independence. FundingNational Institute for Health Research (NIHR) Health Technology Assessment.