This study explores intergenerational co-residence, explicitly focusing on the decision-making factors of older adults and their adult children. While previous research has touched on this topic, only a few studies have truly evaluated the factors driving both generations’ willingness to embrace this living arrangement. This study systematically reviews the factors influencing older and younger adults’ willingness to live in intergenerational households. Systematic searches were conducted through five databases: CINAHL, Embase, PsycINFO, PubMed, and Scopus; all studies until September 2022. Of the 467 articles initially identified, 17 articles were retained for data extraction. Extracted data were divided into two groups: older people’s and adult children's perspectives. Data extraction revealed six factors influencing older adults’ decision to live with their children, encompassing financial circumstances, health conditions, kinship systems, marital status, level of education, and number of family members. Similarly, these factors are relevant for adult children, except for health conditions. The interconnection between these factors and their dynamics is contingent upon the specific context of each region’s population. © 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.