Wendy Sarah Garrett is an American microbiologist who is the Irene Heinz Given Professor of Immunology and Infectious Diseases at the Harvard Chan School of Public Health.

[3] She is interested in the interplay between the gastrointestinal immune system and the gut microbiome, particularly in the context of inflammatory bowel disease and colorectal cancer.

She identified specific microbial species, pathways, and metabolites that impact health and disease states.

[citation needed] Garrett has investigated the microbes and immune cells that play a role in carcinogenesis and intestinal homeostasis.

[citation needed] Garrett has shown that Fusobacterium nucleatum, a microbe of the mouth, is abundant in colon tumors.