This article introduces ‘activist entrepreneuring’ to suggest a fresh understanding of entrepreneuring which foregrounds how constraints of imagination are removed through critical speech. Specifically, we link Michel Foucault's work on parrhesia, or courageous speech, and various literatures on (utopian) imagination to discuss ‘disruptive truth-telling’ as the generative mechanism of activist entrepreneuring whose transformative force resides in breaking free from existing limitations of collective imagination, or what we refer to as the ‘orthodox social imaginary’. We use the activist group Yes Men to develop a process model which throws into sharper relief how disruptive truth-telling is employed, on the one hand, to expose and problematize the boundaries of collective imagination, and, on the other, to create ‘possible worlds’ that prefigure ways of doing business that are consistent with broader societal interest. The three interrelated objectives of this article are: first, to make creative use of the humanities to emphasize how disruptive truth-telling actualizes possibilities for imagining future realities that seem impossible from the standpoint of dominant imagination. Second, to make the case for seeing changes of collective imagination as a genuine entrepreneurial accomplishment. And third, to identify boundary conditions that help us strengthen the explanatory power of our theorizing on disruptive truth-telling.