Gary Bruce Ruvkun (born March 26, 1952) is an American molecular biologist and Nobel laureate at Massachusetts General Hospital and professor of genetics at Harvard Medical School in Boston.

Ruvkun was awarded the 2024 Nobel Prize in Physiology or Medicine for the discovery of microRNA and its role in post-transcriptional gene regulation.

Ruvkun completed postdoctoral research with Robert Horvitz at the Massachusetts Institute of Technology (MIT) and Walter Gilbert of Harvard.

[17] When siRNAs of the same 21-22 nucleotide size as lin-4 and let-7 were discovered in 1999 by Hamilton and Baulcombe in plants,[18] the fields of RNAi and miRNAs suddenly converged.

In a collaborative effort, the Mello and Ruvkun labs showed that the first known components of RNA interference and their paralogs, Dicer and the PIWI proteins, are used by both miRNAs and siRNAs.

Klass[26] Johnson[27] and Kenyon[28] showed that the developmental arrest program mediated by mutations in age-1 and daf-2 increase C. elegans longevity.

[32] The Ruvkun lab in collaboration with Maria Zuber at MIT, Chris Carr (now at Georgia Tech), and Michael Finney (now a San Francisco biotech entrepreneur) has been developing protocols and instruments that can amplify and sequence DNA and RNA to search for life on another planet that is ancestrally related to the Tree of Life on Earth.

[34] In 2012, Ruvkun made an original contribution to the field of immunology with the publication of a featured paper in the journal Cell describing an elegant mechanism for innate immune surveillance in animals that relies on the monitoring of core cellular functions in the host, which are often sabotaged by microbial toxins during the course of infection.

[35] In 2019, Ruvkun, together with Chris Carr, Mike Finney and Maria Zuber,[36] presented the argument that the appearance of sophisticated microbial life on Earth soon after it cooled, and the recent discoveries of hot Jupiters and disruptive planetary migrations in exoplanet systems favors the spread of DNA-based microbial life across the galaxy.