Piet Gros (born July 31, 1962 in Dokkum) is a Dutch chemist and professor biomacromolecular crystallography at Utrecht University.

In 2010 he received the NWO Spinoza Prize for the elucidation of the three-dimensional structure of the C3 protein, which plays a central role in the complement system and contributes to innate immunity.

Five years later Gros received his PhD degree cum laude at the same university, with a thesis on protein crystallography.

In 1994 Gros was given a position at Utrecht University to conduct experimental research towards new applications for protein crystallography.

[1] Gros received an ERC Advanced grant of the European Research Council in 2008,[2] is a member of the Royal Netherlands Academy of Arts and Sciences (KNAW) since 2010[3] and in April 2013, Gros became Knight in the Order of the Netherlands Lion, when he received a Royal Decoration for his scientific achievements.