["Business Strategy and the Environment, Volume 35, Issue 5, Page 6846-6865, July 2026. ", "\nABSTRACT\nCollaborations with nonprofits can enhance firms' legitimacy, yet the relationship between their communication and corporate environmental legitimacy remains poorly understood. Furthermore, research lacks an analysis of the communication of business‐nonprofit collaborations through multiple actors' perspectives. Employing a mixed‐methods content analysis, we analyze 440 firm, nonprofit and media communications on 91 business‐nonprofit collaborations involving Italian firms in environmentally sensitive industries. Our exploratory results indicate that firms' communication is influenced by their environmental legitimacy—firms with stronger environmental legitimacy tend to frame collaborations as substantive rather than symbolic efforts. Furthermore, the media, unlike nonprofit partners, emphasize the symbolic nature of corporate involvement and adopt a negative tone when covering collaborations by firms with weaker environmental legitimacy. Interpreting our findings, we propose that less legitimate firms prioritize pragmatic rather than moral forms of legitimacy in their communication, and vice versa. Our results contribute to research and inform practice by deepening the empirical and conceptual understanding of the relationship between corporate environmental legitimacy, strategic legitimation objectives, and the framing of sustainability communication.\n"]