José Carlos Caetano Xavier is a Portuguese scientist (marine biologist) and polar explorer.

Xavier is a professor and principal investigator of the Institute of Marine Research of the University of Coimbra[1](Portugal) and at the British Antarctic Survey.

[2] Xavier co-founded the Association of Polar Early Career Scientists and is also a member of the Education and Outreach sub-committee of the International Polar Year.

He was involved in the institutional efforts for Portugal to join the Scientific Committee for Antarctic Research (2006), European Polar Board (2007) and signing the Antarctic Treaty (2010).

In 2011, Xavier was the youngest recipient of the Martha T. Muse Prize for his work on science and politics in the Antarctic[3]