Isabelle Stengers (/ˈstɛŋərs/; French: [stɑ̃ɡɛʁs]; born 1949) is a Belgian philosopher, noted for her work in the philosophy of science. She has written books on Chaos Theory with Ilya Prigogine, the Russian-Belgian physical chemist and Nobel Laureate noted for his work on dissipative structures, complex systems, and irreversibility, especially Order out of Chaos and The End of Certainty: Time, Chaos and the New Laws of Nature. Stengers and Prigogine often draw from the work of Deleuze, treating him as an important philosophical source to think through questions regarding irreversibility and the universe as an open system. Stengers' most recent work has turned to her proposition of Cosmopolitics, a key aspect of which Bruno Latour refers to as the "progressive composition of a common world" in which the non-human and the human are intimately entwined, and secondly, her revisiting and pragmatic modulation of the speculative philosophy of Alfred North Whitehead.
Stengers is the daughter of the historian Jean Stengers. She studied chemistry, graduating with a degree in the subject from the Université Libre de Bruxelles.
Her research interests include the philosophy of science and the history of science. She holds her Professorship in the Philosophy of Science at the Université Libre de Bruxelles and received the grand prize for philosophy from the Académie Française in 1993. Stengers has written on English philosopher Alfred North Whitehead; other work has included Continental philosophers such as Michel Serres, Gilbert Simondon and Gilles Deleuze. Stengers has also collaborated with psychiatrist Leon Chertok, and the sociologist of science Bruno Latour.