Senior (shortened as Sr.) means "the elder" in Latin and is often used as a suffix for the elder of two or more people in the same family with the same given name, usually a parent or grandparent. It may also refer to:
- Senior (name), a surname or given name
- Senior (education), a student in the final year of high school, college or university
- Senior citizen, a common designation for a person 65 and older in UK and US English
- Senior (athletics), an age athletics category
- Senior status, form of semi-retirement for United States federal judges
- Senior debt, a form of corporate finance
- Senior producer, a title given usually to the second most senior person of a film of television production.