How do multiple poets speak at once, and what purpose can it serve? Poetry collaborations can involve sophisticated layerings of voice and impositions of meaning, depending on the intentions of the poets involved. In this article, a theory of ‘palimpsestuous’ poetic voices will be substantiated in the case of poetry collections where these voices fluctuate and come together to selectively promote certain ideas or issues. Two poetry collaborations—Speedfactory by Bernard Cohen, John Kinsella, McKenzie Wark, and Terri-ann White, and Speaking Geographies, an on-going poetry project by this article’s authors Siobhan Hodge and Rosalind McFarlane—will be examined in detail. In the case of these two collections, environmentalist concerns are particularly highlighted by their engagements with poetic voices. As this article will demonstrate, collaborations offer poets unique opportunities to set up contrasts between the personal and the communal, coming together with great effect to promote or condemn issues or values.