The aim of this research was to understand the structural features of large cross-sector social partnerships (CSSPs) and their resulting partner outcomes. This study analyzed and compared the partnership structures of three large CSSPs, each from a different continent: Barcelona + Sustainable in Barcelona, Spain; Gwangju Council for Sustainable Development in Gwangju, South Korea; and Sustainable Montreal in Montreal, Canada. Based on a survey of the partners in each of the three partnerships, the partner outcomes were also determined and compared. Building on these findings and using abductive analysis, the relationships between the partnerships’ structural features and partner outcomes are considered. An updated set of seven structural features for studying large cross-sector partnerships is offered. The empirical findings show some differences between the partnership designs and between the partner outcomes of the three partnerships. The experiences of the civil society, private sector and public sector partners in each of the cases were relatively similar, showing that in large partnerships, the sector was less relevant than in small partnerships.