Paul James Sidwell is an Australian linguist based in Canberra, Australia, who has held research and lecturing positions at the Australian National University.

Sidwell, who is also an expert and consultant in forensic linguistics, is most notable for his work on the historical linguistics of the Austroasiatic language family, and has published reconstructions of the Austroasiatic, Bahnaric, Katuic, Palaungic, Khasic, and Nicobaric proto-languages.

In 2001, Sidwell was appointed as a collaborating scientist at the Max Planck Institute for Evolutionary Anthropology, Leipzig.

From 2007 to 2011 he was director of the Mon-Khmer Language Project at the Center for Research in Computational Linguistics at Bangkok, and from 2012 to 2016 an Australian Research Council Future Fellow at the Australian National University, working on the Austroasiatic Lexicon Project.

Since 2017 he has been a partner at Language Intelligence, and in 2017/2018 was an honorary lecturer of the Australian National University.