Transitioning from linear to circular production systems requires interactions that include cross‐sectoral collaboration in networks. Understanding the role of collaboration within these networks can support the transition to a circular economy. To understand cross‐sectoral collaborative endeavors, this paper develops a collaboration framework for circular economy by combining and interlinking three theories: the relational view, open innovation, and dynamic capabilities. The framework is applied to the Circle‐House‐Project, a cross‐sectoral collaborative project aimed at scaling circular economy in the Danish construction sector. The explorative data included desk research and 15 semistructured interviews with expert project partners. The findings were transcribed, structured, coded, condensed, and categorized to provide an illustrative case based on a lighthouse project in the construction sector, affording a novel understanding of how cross‐sectoral collaboration can support advancing circular economy practices by developing knowledge‐sharing routines and ecocentric dynamic capabilities. The paper provides insights for academics and practitioners from a broad field by combining diverse interdisciplinary perspectives to unlock the potential of cross‐sectoral collaboration for advancing circular economy.