Social isolation and loneliness are increasingly recognised as significant public health concerns among informal caregivers of people with dementia. While caregiving is often associated with reduced social engagement and increased psychological burden, the extent and nature of its relationship with social wellbeing outcomes remain unclear. This systematic review aims to synthesise existing evidence on the relationships between informal caregiving and social isolation, loneliness, and related constructs among informal caregivers of community-dwelling people with dementia or mild cognitive impairment. A systematic search was conducted across four electronic databases - PsycINFO, Embase, MEDLINE, and CINAHL, alongside grey literature sources. Eligible studies included quantitative, qualitative, and mixed-methods research examining caregiving status or caregiving-related characteristics (e.g., caregiving intensity, burden) in relation to social wellbeing outcomes. Title/abstract and full-text screening were conducted in accordance with predefined inclusion criteria. Preliminary findings suggest that informal caregiving is consistently associated with higher levels of loneliness and reduced social connectedness. Emerging evidence indicates that this relationship may be shaped by caregiving demands, loss of social roles, and barriers to maintaining social relationships. Qualitative studies further highlight the role of emotional strain and perceived lack of support in exacerbating social isolation. This review will provide a comprehensive synthesis of current evidence and identify key mechanisms linking caregiving and social wellbeing. Findings have implications for the development of targeted interventions and services aimed at reducing social isolation among dementia caregivers, particularly within diverse cultural contexts.