Online platforms are significantly transforming the way we work, the way we create and distribute value and the way we relate and engage with one another within modern society. These trends became even more pronounced throughout the COVID-19 context. Digital technology, however, can present both possibilities and problems. So far, the platform sector has been dominated by ‘platform capitalism’, where profit, competition and private ownership are prioritised over cooperative social relationships of care and mutual support. These platform capitalism initiatives are often critiqued for exploiting labor, the resources of service users and for avoiding regulation. Platform capitalism initiatives are just one potential pathway for the digital technology sector, with academics identifying two other directions, including a costly system of state regulation in response to platform capitalism and the development of more democratically owned and/or governed sharing arrangements. This latter form of ‘sharing economy’, embedded in solidarity, reciprocity and grassroots cooperation through shared access to resources, has been widely promoted as a positive direction for society. Achieving a democratically owned and governed ‘sharing economy’, however, requires a rethink of the political and regulatory landscape and the social relations underpinning digital technology initiatives. In rethinking the ‘sharing economy’ social relation foundations, advocates highlight the potential of commons governance and platform cooperativism. Commons governance advances a deep contributory democracy that aims to maximise community benefit through the prioritisation of the rights of accessibility to resources. Within the commons literature, platform cooperatives are encouraged as an organisational model for delivering on commons processes and outcomes. As cooperatively owned and democratically governed businesses that utilise an online platform to facilitate their services, platform cooperatives potentially bring together the benefits of cooperative governance with internet technology. In progressing a change in ownership structures, including more democratic participation and fairer working conditions, platform cooperatives have the potential to contribute to a sharing economy model that is enriching for community. The aged care sector has been identified as particularly at risk in regard to expanding platform capitalism, and, therefore, holds significant potential for positive platform cooperative interventions. Accordingly, this thesis explores the real-world experiences of platform cooperatives within the rapidly growing aged care sector and the governing practices influencing commons care processes and outcomes. As an emerging model, there is limited theoretical and empirical knowledge regarding care focused platform cooperatives. To achieve quality aged care models, whilst balancing the needs of the ageing, the broader community, and the aged care sector, it is critical to understand what governance practices platform cooperatives need to sustain and improve on for enhancing commons care processes and outcomes. As such, the primary research question guiding the thesis is what are the main aged care platform cooperative governance practices influencing commons care processes and outcomes? In contributing to platform cooperative governance empirical evidence, the thesis utilises an organisational case-study approach. The three case-studies align with the main care focused platform cooperative legal forms identified within the platform cooperative literature, and incorporate: i) an ethnographic case-study of a Melbourne, Australia based company limited by guarantee experiment (namely “The Sharing Tree project through Uniting Vic Tas”) ii) a qualitative case-study of a New South Wales, Australia based worker owned cooperative (namely “the Cooperative Life”) iii) a more restricted shadow case-study of a United Kingdom based multi-stakeholder cooperative (namely “Equal Care Cooperative”). Through these organisational case-studies, and the employment of semi-structured interview and ethnographic observation data collection methods, platform cooperative participants reveal the organisational governance practices that contribute to commons care processes and outcomes. A Critical Institutional Analysis and Development (CIAD) Framework assists in contextualising these governance practices; in positioning governance as socially constructed and emerging from the interplay of historically and geographically embedded agency and structure. This multi-faceted focus highlights the platform cooperative organisational form as a site of power laden social interactions, where individuals are building, improving on and working against commons care processes and outcomes. Furthermore, this integrated research focus reveals platform cooperative governance practices as occurring within a complex context of state-led consumer directed care reform within the Australian aged care context; which is shaping both ‘compliant’ and ‘resistant’ platform cooperative governance practices.