Antonina Roll-Mecak (born in Sibiu, Romania) is a Romanian-born American molecular biophysicist. She is currently the Senior Investigator and Chief of the Unit of Cell Biology and Biophysics at the National Institutes of Health. She holds appointments at the National Institute of Neurological Disorders and Stroke and at the Biochemistry and Biophysics Center of the National Heart, Lung and Blood Institute. Roll-Mecak is known for her work on cytoskeletal regulation, mechanisms of microtubule severing enzymes (spastin and Katanin) and microtubule repair, and for her pioneering work in deciphering the complexities of the tubulin code. Her work is relevant to the treatment of cancer and nervous system disorders.