Assistive telecare systems (ATSs) have great potential to be beneficial for informal carers (ICs) providing long-term care to older people (OP). However, little is known about ATS acceptance among ICs. This scoping study aims to investigate various factors that influence the ICs' acceptance of ATSs over time in the pre- and post-implementation phases. A five-stage scoping study was conducted. A systematic search of five bibliographic databases (Science Direct, Scopus, CINAHL, PubMED and Proquest Social Sciences Database) was conducted in September 2020, supplemented by a round of grey literature searches. Using the established selection criteria, 37 publications published between 2000 and September 2020 were included. The data were analysed with Atlas.ti 8 using content-based analysis and a combination of deductive and inductive approaches. The results show that work on understanding acceptance of ATS only gained wider attention after 2010. Seven key factors of ATS acceptance were identified: benefits and concerns about ATS, care situation, the influence of the OP, carer characteristics, perceived need to use and social influence. Several subfactors were also found. The post-intervention acceptance factors were found to be more nuanced than the pre-implementation factors, indicating that first-hand experience with ATSs enabled study participants to provide a more tangible, extensive and in-depth overview of the various ATS acceptance factors. This scoping review is useful for ATS developers, providers, health and social care scholars and practitioners, policy makers and commissioners, all of whom seek to improve and facilitate the provision of long-term care in the community.